Aldehyde-tagged immunoglobulin polypeptides and methods of use thereof

ABSTRACT

The present disclosure provides aldehyde-tagged immunoglobulin (Ig) polypeptides that can be converted by a formylglycine-generating enzyme to produce a 2-formylglycine (FGly)-modified Ig polypeptide. An FGly-modified Ig polypeptide can be covalently and site-specifically bound to a moiety of interest to provide an Ig conjugate. The disclosure also encompasses methods of production of such aldehyde-tagged Ig polypeptides, FGly-modified Ig polypeptides, and Ig conjugates, as well as methods of use of same.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority benefit of U.S. provisional applicationSer. No. 61/433,042, filed Jan. 14, 2011, which application isincorporated herein by reference in its entirety.

INTRODUCTION

Antibodies find use in various diagnostic and therapeutic applications.Antibodies can also be used to deliver drugs. However, conjugation of adrug to an antibody can be difficult to control, resulting in aheterogeneous mixture of conjugates that differ in the number of drugmolecules attached. This can make controlling the amount administered toa patient difficult.

LITERATURE

U.S. Patent Publication No. 2010/0210543; WO 2010/096394; U.S. PatentPublication No. 2008/0187956; WO 2009/120611.

SUMMARY

The present disclosure provides aldehyde-tagged immunoglobulin (Ig)polypeptides that can be converted by a formylglycine-generating enzymeto produce a formylglycine (FGly)-modified Ig polypeptide. AnFGly-modified Ig polypeptide can be covalently and site-specificallybound to a moiety of interest to provide an Ig conjugate. The disclosurealso encompasses methods of production of such aldehyde-tagged Igpolypeptides, FGly-modified Ig polypeptides, and Ig conjugates, as wellas methods of use of same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a site map showing possible modification sites forgeneration of an aldehyde tagged Ig polypeptide. The upper sequence isthe amino acid sequence of the conserved region of an IgG1 light chainpolypeptide (SEQ ID NO:1) and shows possible modification sites in an Iglight chain; the lower sequence is the amino acid sequence of theconserved region of an Ig heavy chain polypeptide (SEQ ID NO:228;GenBank Accession No. AAG00909) and shows possible modification sites inan Ig heavy chain. The heavy and light chain numbering is based on thefull-length heavy and light chains.

FIG. 1B depicts an alignment of immunoglobulin heavy chain constantregions for IgG1 (SEQ ID NO:2), IgG2 (SEQ ID NO:4), IgG3 (SEQ ID NO:3),IgG4 (SEQ ID NO:5), and IgA (SEQ ID NO:6), showing modification sites atwhich aldehyde tags can be provided in an immunoglobulin heavy chain.The heavy and light chain numbering is based on the full-heavy and lightchains.

FIG. 1C depicts an alignment of immunoglobulin light chain constantregions (SEQ ID NOS:1 and 7-10), showing modification sites at whichaldehyde tags can be provided in an immuoglobulin immunoglobulin lightchain.

FIG. 2 presents a scheme for expression of aldehyde-tagged antibodiesand their subsequent chemical conjugation.

FIG. 3 depicts solvent-accessible loop regions in anti-CD19 light chain(upper sequence (SEQ ID NO:11)) and heavy chain (lower sequence (SEQ IDNO:12)) constant regions, with an LCTPSR (SEQ ID NO:17) sulfatase motifin the heavy chain constant region. The signal peptide is shown inlower-case letters; the variable region is underlined;solvent-accessible loop regions in the constant regions are shown inbold and underlined. The LCTPSR (SEQ ID NO:17) sequence is shown in boldand double underlining.

FIG. 4 depicts protein blot analysis of aldehyde-tagged anti-CD19 andaldehyde-tagged anti-CD22 antibodies. The left panel provides aschematic of an antibody and indicates the relative positions ofexamples of sites of aldehyde tag modification in an Ig heavy chain CH1region (“CH1 (A)”, “CH1 (B)”, “CH1 (C)”), Ig heavy chain CH2 region(“CH2 (A)”, “CH2 (B)”, “CH2 (C)”), CH2/3 region (“CH2/CH3”), andC-terminal region (“C-terminal”).

FIG. 5 depicts Western blot analysis of a) aldehyde-tagged anti-CD22antibodies chemically conjugated with aminooxy-FLAG® (Panel A); and b)Western blot analysis of aldehyde-tagged anti-CD19 antibodies andaldehyde-tagged anti-CD22 antibodies chemically conjugated withaminooxy-FLAG®.

FIGS. 6A and 6B depict a nucleotide sequence (FIG. 6A; (SEQ ID NO:13))encoding the heavy chain of a CD22-specific IgG1 antibody, and theencoded amino acid sequence (FIG. 6B; (SEQ ID NO:14)). The end of thesignal sequence is denoted by “/”. The end of the variable region andthe beginning of the constant region is denoted “//”.

FIGS. 7A and 7B depict a nucleotide sequence (FIG. 7A; (SEQ ID NO:15))encoding an aldehyde-tagged anti-CD22 immunoglobulin (Ig) heavy chain(“CH1 (A) LCTPSR”), and the encoded amino acid sequence (FIG. 7B; (SEQID NO:16)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in CH1 isunderlined. The end of the signal sequence is denoted by “/”. The end ofthe variable region and the beginning of the constant region is denoted“//”.

FIGS. 8A and 8B depict a nucleotide sequence (FIG. 8A; (SEQ ID NO:18))encoding an aldehyde-tagged anti-CD22 immunoglobulin (Ig) heavy chain(“CH1 (B) LCTPSR”), and the encoded amino acid sequence (FIG. 8B; (SEQID NO:19)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in CH1 isunderlined. The end of the signal sequence is denoted by “/”. The end ofthe variable region and the beginning of the constant region is denoted“//”.

FIGS. 9A and 9B depict a nucleotide sequence (FIG. 9A; (SEQ ID NO:20))encoding an aldehyde-tagged anti-CD22 immunoglobulin (Ig) heavy chain(“CH1 (C) LCTPSR”), and the encoded amino acid sequence (FIG. 9B; (SEQID NO:21)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in CH1 isunderlined. The end of the signal sequence is denoted by “/”. The end ofthe variable region and the beginning of the constant region is denoted“//”.

FIGS. 10A and 10B depict a nucleotide sequence (FIG. 10A; (SEQ IDNO:22)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain (“CH1 (C)LATPSR”), and the encoded amino acid sequence (FIG. 10B; (SEQ IDNO:23)). The LATPSR (SEQ ID NO:24) sulfatase motif sequence in CH1 isunderlined. The end of the signal sequence is denoted by “/”. The end ofthe variable region and the beginning of the constant region is denoted“//”.

FIGS. 11A and 11B depict a nucleotide sequence (FIG. 11A; (SEQ IDNO:25)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain (“CH2 (A)LCTPSR”), and the encoded amino acid sequence (FIG. 11B; (SEQ IDNO:26)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in CH2 isunderlined. The end of the signal sequence is denoted by “/”. The end ofthe variable region and the beginning of the constant region is denoted“//”.

FIGS. 12A and 12B depict a nucleotide sequence (FIG. 12A; (SEQ IDNO:27)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain (“CH2 (B)LCTPSR”), and the encoded amino acid sequence (FIG. 12B; (SEQ IDNO:28)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in CH2 isunderlined. The end of the signal sequence is denoted by “/”. The end ofthe variable region and the beginning of the constant region is denoted“//”.

FIGS. 13A and 13B depict a nucleotide sequence (FIG. 13A; (SEQ IDNO:29)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain (“CH2 (C)LCTPSR”), and the encoded amino acid sequence (FIG. 13B; (SEQ IDNO:30)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in CH2 isunderlined. The end of the signal sequence is denoted by “/”. The end ofthe variable region and the beginning of the constant region is denoted“//”.

FIGS. 14A and 14B depict a nucleotide sequence (FIG. 14A; (SEQ IDNO:31)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain (“CH2(C)”), and the encoded amino acid sequences (FIG. 14B; (SEQ ID NO:32)).The LATPSR (SEQ ID NO:24) sulfatase motif sequence in CH2 is underlined.

FIGS. 15A and 15B depict a nucleotide sequence (FIG. 15A; (SEQ IDNO:33)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain (“CH2/CH3LCTPSR”), and the encoded amino acid sequences (FIG. 15B; (SEQ IDNO:34)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in CH2/CH3is underlined. The end of the signal sequence is denoted by “/”. The endof the variable region and the beginning of the constant region isdenoted “//”.

FIGS. 16A and 16B depict a nucleotide sequence (FIG. 16A; (SEQ IDNO:35)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain (“CH2/CH3LATPSR”), and the encoded amino acid sequences (FIG. 16B; (SEQ IDNO:36)). The LATPSR (SEQ ID NO:24) sulfatase motif sequence in CH2/CH3is underlined. The end of the signal sequence is denoted by “/”. The endof the variable region and the beginning of the constant region isdenoted “//”.

FIGS. 17A and 17B depict a nucleotide sequence (FIG. 17A; (SEQ IDNO:37)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain(“C-terminal LCTPSR”), and the encoded amino acid sequences (FIG. 17B;(SEQ ID NO:38)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence inthe C-terminal region is underlined. The end of the signal sequence isdenoted by “/”. The end of the variable region and the beginning of theconstant region is denoted “//”.

FIGS. 18A and 18B depict a nucleotide sequence (FIG. 18A; (SEQ IDNO:39)) encoding an aldehyde-tagged anti-CD22 Ig heavy chain(“C-terminal LATPSR”), and the encoded amino acid sequences (FIG. 18B;(SEQ ID NO:40)) The LATPSR (SEQ ID NO:24) sulfatase motif sequence inthe C-terminal region is underlined. The end of the signal sequence isdenoted by “/”. The end of the variable region and the beginning of theconstant region is denoted “//”.

FIGS. 19A and 19B depict a nucleotide sequence (FIG. 19A; (SEQ IDNO:41)) encoding a CD22-specific human Ig kappa light chain, and theencoded amino acid sequence (FIG. 19B; (SEQ ID NO:42)). The end of thesignal sequence is denoted by “/”. The end of the variable region andthe beginning of the constant region is denoted “//”.

FIGS. 20A and 20B depict a nucleotide sequence (FIG. 20A; (SEQ IDNO:43)) encoding an aldehyde-tagged anti-CD22 Ig kappa light chain, andthe encoded amino acid sequences (FIG. 20B; (SEQ ID NO:44)). The LCTPSR(SEQ ID NO:17) sulfatase motif sequence is underlined. The end of thesignal sequence is denoted by “/”. The end of the variable region andthe beginning of the constant region is denoted “//”.

FIGS. 21A and 21B depict a nucleotide sequence (FIG. 21A; (SEQ IDNO:45)) encoding an aldehyde-tagged anti-CD22 Ig kappa light chain, andthe encoded amino acid sequences (FIG. 21B; (SEQ ID NO:46)). The LATPSR(SEQ ID NO:24) sulfatase motif sequence is underlined. The end of thesignal sequence is denoted by “/”. The end of the variable region andthe beginning of the constant region is denoted “//”.

FIGS. 22A and 22B depict a nucleotide sequence (FIG. 22A; (SEQ IDNO:47)) encoding the heavy chain of a CD19-specific IgG1 antibody, andthe encoded amino acid sequence (FIG. 22B; (SEQ ID NO:48)). The end ofthe signal sequence is denoted by “/”. The end of the variable regionand the beginning of the constant region is denoted “//”.

FIGS. 23A and 23B depict a nucleotide sequence (FIG. 23A; (SEQ IDNO:49)) encoding an aldehyde-tagged anti-CD19 Ig heavy chain (“CH1 (C)LCTPSR”), and the encoded amino acid sequences (FIG. 23B; (SEQ IDNO:50)) (CHI (C)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence inthe CH1 region is underlined. The end of the signal sequence is denotedby “/”. The end of the variable region and the beginning of the constantregion is denoted “//”.

FIGS. 24A and 24B depict a nucleotide sequence (FIG. 24A; (SEQ IDNO:51)) encoding an aldehyde-tagged anti-CD19 Ig heavy chain (“CH1 (C)LATPSR”), and the encoded amino acid sequences (FIG. 24B; (SEQ IDNO:52)). The LATPSR (SEQ ID NO:24) sulfatase motif sequence in the CH1region is underlined. The end of the signal sequence is denoted by “/”.The end of the variable region and the beginning of the constant regionis denoted “//”.

FIGS. 25A and 25B depict a nucleotide sequence (FIG. 25A; (SEQ IDNO:53)) encoding an aldehyde-tagged anti-CD19 Ig heavy chain (“CH2 (B)LCTPSR”), and the encoded amino acid sequences (FIG. 25B; (SEQ IDNO:54)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in the CH2region is underlined. The end of the signal sequence is denoted by “/”.The end of the variable region and the beginning of the constant regionis denoted “//”.

FIGS. 26A and 26B depict a nucleotide sequence (FIG. 26A; (SEQ IDNO:55)) encoding an aldehyde-tagged anti-CD19 Ig heavy chain (“CH2 (B)LATPSR”), and the encoded amino acid sequences (FIG. 26B; (SEQ IDNO:56)). The LATPSR (SEQ ID NO:24) sulfatase motif sequence in the CH2region is underlined. The end of the signal sequence is denoted by “/”.The end of the variable region and the beginning of the constant regionis denoted “//”.

FIGS. 27A and 27B depict a nucleotide sequence (FIG. 27A; (SEQ IDNO:57)) encoding an aldehyde-tagged anti-CD19 Ig heavy chain (“CH2/CH3LCTPSR”), and the encoded amino acid sequences (FIG. 27B; (SEQ IDNO:58)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence in theCH2/CH3 region is underlined. The end of the signal sequence is denotedby “/”. The end of the variable region and the beginning of the constantregion is denoted “//”.

FIGS. 28A and 28B depict a nucleotide sequence (FIG. 28A; (SEQ IDNO:59)) encoding an aldehyde-tagged anti-CD19 Ig heavy chain (“CH2/CH3LATPSR”), and the encoded amino acid sequences (FIG. 28B; (SEQ IDNO:60)). The LATPSR (SEQ ID NO:24) sulfatase motif sequence in theCH2/CH3 region is underlined. The end of the signal sequence is denotedby “/”. The end of the variable region and the beginning of the constantregion is denoted “//”.

FIGS. 29A and 29B depict a nucleotide sequence (FIG. 29A; (SEQ IDNO:61)) encoding an aldehyde-tagged anti-CD19 Ig heavy chain(“C-terminal LCTPSR”), and the encoded amino acid sequences (FIG. 29B;(SEQ ID NO:62)). The LCTPSR (SEQ ID NO:17) sulfatase motif sequence inthe C-terminal region is underlined. The end of the signal sequence isdenoted by “/”. The end of the variable region and the beginning of theconstant region is denoted “//”.

FIGS. 30A and 30B depict a nucleotide sequence (FIG. 30A; (SEQ IDNO:63)) encoding an aldehyde-tagged anti-CD19 Ig heavy chain(“C-terminal LATPSR”), and the encoded amino acid sequences (FIG. 30B;(SEQ ID NO:64)). The LATPSR (SEQ ID NO:24) sulfatase motif sequence inthe C-terminal region is underlined. The end of the signal sequence isdenoted by “/”. The end of the variable region and the beginning of theconstant region is denoted “//”.

FIGS. 31A and 31B depict a nucleotide sequence (FIG. 31A; (SEQ IDNO:65)) encoding a CD19-specific human Ig kappa light chain, and theencoded amino acid sequence (FIG. 31B; (SEQ ID NO:66)). The end of thesignal sequence is denoted by “/”. The end of the variable region andthe beginning of the constant region is denoted “//”.

FIGS. 32A and 32B depict a nucleotide sequence (FIG. 32A; (SEQ IDNO:67)) encoding an aldehyde-tagged anti-CD19 Ig kappa light chain, andthe encoded amino acid sequences (FIG. 32B; (SEQ ID NO:68)). The LCTPSR(SEQ ID NO:17) sulfatase motif sequence is underlined. The end of thesignal sequence is denoted by “/”. The end of the variable region andthe beginning of the constant region is denoted “//”.

FIGS. 33A and 33B depict a nucleotide sequence (FIG. 33A; (SEQ IDNO:69)) encoding an aldehyde-tagged anti-CD19 Ig kappa light chain, andthe encoded amino acid sequences (FIG. 33B; (SEQ ID NO:70)). The LATPSR(SEQ ID NO:24) sulfatase motif sequence is underlined. The end of thesignal sequence is denoted by “/”. The end of the variable region andthe beginning of the constant region is denoted “//”.

DEFINITIONS

The terms “polypeptide,” “peptide,” and “protein” are usedinterchangeably herein to refer to a polymeric form of amino acids ofany length. Unless specifically indicated otherwise, “polypeptide,”“peptide,” and “protein” can include genetically coded and non-codedamino acids, chemically or biochemically modified or derivatized aminoacids, and polypeptides having modified peptide backbones. The termincludes fusion proteins, including, but not limited to, fusion proteinswith a heterologous amino acid sequence, fusions with heterologous andhomologous leader sequences, proteins which contain at least oneN-terminal methionine residue (e.g., to facilitate production in arecombinant bacterial host cell); immunologically tagged proteins; andthe like.

“Native amino acid sequence” or “parent amino acid sequence” are usedinterchangeably herein in the context of an immunoglobulin to refer tothe amino acid sequence of the immunoglobulin prior to modification toinclude a heterologous aldehyde tag.

The term “antibody” is used in the broadest sense and includesmonoclonal antibodies (including full length monoclonal antibodies),polyclonal antibodies, and multispecific antibodies (e.g., bispecificantibodies), humanized antibodies, single-chain antibodies, chimericantibodies, antibody fragments (e.g., Fab fragments), and the like. Anantibody is capable of binding a target antigen. (Janeway, C., Travers,P., Walport, M., Shlomchik (2001) Immuno Biology, 5th Ed., GarlandPublishing, New York). A target antigen can have one or more bindingsites, also called epitopes, recognized by complementarity determiningregions (CDRs) formed by one or more variable regions of an antibody.

“Immunoglobulin polypeptide” as used herein refers to a polypeptidecomprising at least a constant region of a light chain polypeptide or atleast a constant region of a heavy chain polypeptide.

An immunoglobulin polypeptide immunoglobulin light or heavy chainvariable region is composed of a framework region (FR) interrupted bythree hypervariable regions, also called “complementarity determiningregions” or “CDRs”. The extent of the framework region and CDRs havebeen defined (see, “Sequences of Proteins of Immunological Interest,” E.Kabat et al., U.S. Department of Health and Human Services, 1991). Theframework region of an antibody, that is the combined framework regionsof the constituent light and heavy chains, serves to position and alignthe CDRs. The CDRs are primarily responsible for binding to an epitopeof an antigen.

The term “natural antibody” refers to an antibody in which the heavy andlight chains of the antibody have been made and paired by the immunesystem of a multi-cellular organism. Spleen, lymph nodes, bone marrowand serum are examples of tissues that produce natural antibodies. Forexample, the antibodies produced by the antibody producing cellsisolated from a first animal immunized with an antigen are naturalantibodies.

Throughout the present disclosure, the numbering of the residues in animmunoglobulin heavy chain and in an immunoglobulin light chain is thatas in Kabat et al., Sequences of Proteins of Immunological Interest, 5thEd. Public Health Service, National Institutes of Health, Bethesda, Md.(1991), expressly incorporated herein by reference.

A “parent Ig polypeptide” is a polypeptide comprising an amino acidsequence which lacks an aldehyde-tagged constant region as describedherein. The parent polypeptide may comprise a native sequence constantregion, or may comprise a constant region with pre-existing amino acidsequence modifications (such as additions, deletions and/orsubstitutions).

In the context of an Ig polypeptide, the term “constant region” is wellunderstood in the art, and refers to a C-terminal region of an Ig heavychain, or an Ig light chain. An Ig heavy chain constant region includesCH1, CH2, and CH3 domains (and CH4 domains, where the heavy chain is μor an ε heavy chain). In a native Ig heavy chain, the CH1, CH2, CH3(and, if present, CH4) domains begin immediately after (C-terminal to)the heavy chain variable (VH) region, and are each from about 100 aminoacids to about 130 amino acids in length. In a native Ig light chain,the constant region begins begin immediately after (C-terminal to) thelight chain variable (VL) region, and is about 100 amino acids to 120amino acids in length.

In some embodiments, a “functional Fc region” possesses an “effectorfunction” of a native sequence Fc region. Exemplary “effector functions”include C1q binding; complement dependent cytotoxicity; Fc receptorbinding; antibody-dependent cell-mediated cytotoxicity (ADCC);phagocytosis; down-regulation of cell surface receptors (e.g. B cellreceptor; BCR), etc. Such effector functions generally require the Fcregion to be combined with a binding domain (e.g. an antibody variabledomain) and can be assessed using various assays that are well known inthe art.

Antibody-dependent cell-mediated cytotoxicity” and “ADCC” refer to acell-mediated reaction in which nonspecific cytotoxic cells that expressFcRs (e.g. Natural Killer (NK) cells, neutrophils, and macrophages)recognize bound antibody on a target cell and subsequently cause lysisof the target cell. The primary cells for mediating ADCC, NK cells,express FcγRIII only, whereas monocytes express FcγRI, FcγRII andFcγRIII

The terms “Fc receptor” or “FcR” are used to describe a receptor thatbinds to the Fc region of an antibody. FcRs are reviewed in Ravetch andKinet, Annu. Rev. Immunol 9:457 92 (1991); Capel et al., Immunomethods4:25 34 (1994); and de Haas et al., J. Lab. Clin. Med. 126:330 41(1995).

The term “humanized antibody” or “humanized immunoglobulin” refers to anon-human (e.g., mouse or rabbit) antibody containing one or more aminoacids (in a framework region, a constant region or a CDR, for example)that have been substituted with a correspondingly positioned amino acidfrom a human antibody. In general, humanized antibodies produce areduced immune response in a human host, as compared to a non-humanizedversion of the same antibody. Antibodies can be humanized using avariety of techniques known in the art including, for example,CDR-grafting (EP 239,400; PCT publication WO 91/09967; U.S. Pat. Nos.5,225,539; 5,530,101; and 5,585,089), veneering or resurfacing (EP592,106; EP 519,596; Padlan, Molecular Immunology 28(4/5):489-498(1991); Studnicka et al., Protein Engineering 7(6):805-814 (1994);Roguska. et al., PNAS 91:969-973 (1994)), and chain shuffling (U.S. Pat.No. 5,565,332). In certain embodiments, framework substitutions areidentified by modeling of the interactions of the CDR and frameworkresidues to identify framework residues important for antigen bindingand sequence comparison to identify unusual framework residues atparticular positions (see, e.g., U.S. Pat. No. 5,585,089; Riechmann etal., Nature 332:323 (1988)). Additional methods for humanizingantibodies contemplated for use in the present invention are describedin U.S. Pat. Nos. 5,750,078; 5,502,167; 5,705,154; 5,770,403; 5,698,417;5,693,493; 5,558,864; 4,935,496; and 4,816,567, and PCT publications WO98/45331 and WO 98/45332. In particular embodiments, a subject rabbitantibody may be humanized according to the methods set forth inUS20040086979 and US20050033031. Accordingly, the antibodies describedabove may be humanized using methods that are well known in the art.

The term “chimeric antibodies” refer to antibodies whose light and heavychain genes have been constructed, typically by genetic engineering,from antibody variable and constant region genes belonging to differentspecies. For example, the variable segments of the genes from a mousemonoclonal antibody may be joined to human constant segments, such asgamma 1 and gamma 3. An example of a therapeutic chimeric antibody is ahybrid protein composed of the variable or antigen-binding domain from amouse antibody and the constant or effector domain from a humanantibody, although domains from other mammalian species may be used.

By “aldehyde tag” or “ald-tag” is meant an amino acid sequence thatcontains an amino acid sequence derived from a sulfatase motif which iscapable of being converted, or which has been converted, by action of aformylglycine generating enzyme (FGE) to contain a 2-formylglycineresidue (referred to herein as “FGly”). The FGly residue generated by anFGE is often referred to in the literature as a “formylglycine”. Stateddifferently, the term “aldehyde tag” is used herein to refer to an aminoacid sequence comprising an “unconverted” sulfatase motif (i.e., asulfatase motif in which the cysteine or serine residues has not beenconverted to FGly by an FGE, but is capable of being converted) as wellas to an amino acid sequence comprising a “converted” sulfatase motif(i.e., a sulfatase motif in which the cysteine or the serine residue hasbeen converted to FGly by action of an FGE).

By “conversion” as used in the context of action of a formylglycinegenerating enzyme (FGE) on a sulfatase motif refers to biochemicalmodification of a cysteine or serine residue in a sulfatase motif to aformylglycine (FGly) residue (e.g., Cys to FGly, or Ser to FGly).

By “genetically-encodable” as used in reference to an amino acidsequence of polypeptide, peptide or protein means that the amino acidsequence is composed of amino acid residues that are capable ofproduction by transcription and translation of a nucleic acid encodingthe amino acid sequence, where transcription and/or translation mayoccur in a cell or in a cell-free in vitro transcription/translationsystem.

The term “control sequences” refers to DNA sequences that facilitateexpression of an operably linked coding sequence in a particularexpression system, e.g. mammalian cell, bacterial cell, cell-freesynthesis, etc. The control sequences that are suitable for prokaryotesystems, for example, include a promoter, optionally an operatorsequence, and a ribosome binding site. Eukaryotic cell systems mayutilize promoters, polyadenylation signals, and enhancers.

A nucleic acid is “operably linked” when it is placed into a functionalrelationship with another nucleic acid sequence. For example, DNA for apresequence or secretory leader is operably linked to DNA for apolypeptide if it is expressed as a preprotein that participates in thesecretion of the polypeptide; a promoter or enhancer is operably linkedto a coding sequence if it affects the transcription of the sequence; ora ribosome binding site is operably linked to a coding sequence if it ispositioned so as to facilitate the initiation of translation. Generally,“operably linked” means that the DNA sequences being linked arecontiguous, and, in the case of a secretory leader, contiguous and inreading frame. Linking is accomplished by ligation or throughamplification reactions. Synthetic oligonucleotide adaptors or linkersmay be used for linking sequences in accordance with conventionalpractice.

The term “expression cassette” as used herein refers to a segment ofnucleic acid, usually DNA, that can be inserted into a nucleic acid(e.g., by use of restriction sites compatible with ligation into aconstruct of interest or by homologous recombination into a construct ofinterest or into a host cell genome). In general, the nucleic acidsegment comprises a polynucleotide that encodes a polypeptide ofinterest (e.g., an aldehyde tagged-Ig protein), and the cassette andrestriction sites are designed to facilitate insertion of the cassettein the proper reading frame for transcription and translation.Expression cassettes can also comprise elements that facilitateexpression of a polynucleotide encoding a polypeptide of interest in ahost cell. These elements may include, but are not limited to: apromoter, a minimal promoter, an enhancer, a response element, aterminator sequence, a polyadenylation sequence, and the like.

As used herein the term “isolated” is meant to describe a compound ofinterest that is in an environment different from that in which thecompound naturally occurs. “Isolated” is meant to include compounds thatare within samples that are substantially enriched for the compound ofinterest and/or in which the compound of interest is partially orsubstantially purified.

As used herein, the term “substantially purified” refers to a compoundthat is removed from its natural environment and is at least 60% free,at least 75% free, at least 80% free, at least 85% free, at least 90%free, at least 95% free, at least 98% free, or more than 98% free, fromother components with which it is naturally associated.

The term “physiological conditions” is meant to encompass thoseconditions compatible with living cells, e.g., predominantly aqueousconditions of a temperature, pH, salinity, etc. that are compatible withliving cells.

By “reactive partner” is meant a molecule or molecular moiety thatspecifically reacts with another reactive partner to produce a reactionproduct. Exemplary reactive partners include a cysteine or serine ofsulfatase motif and an FGE, which react to form a reaction product of aconverted aldehyde tag containing an FGly in lieu of cysteine or serinein the motif. Other exemplary reactive partners include an aldehyde of aformylglycine (FGly) residue of a converted aldehyde tag and an“aldehyde-reactive reactive partner”, which comprises analdehyde-reactive group and a moiety of interest, and which reacts toform a reaction product of a modified aldehyde tagged polypeptide havingthe moiety of interest conjugated to the modified polypeptide through amodified FGly residue.

“N-terminus” refers to the terminal amino acid residue of a polypeptidehaving a free amine group, which amine group in non-N-terminus aminoacid residues normally forms part of the covalent backbone of thepolypeptide.

“C-terminus” refers to the terminal amino acid residue of a polypeptidehaving a free carboxyl group, which carboxyl group in non-C-terminusamino acid residues normally forms part of the covalent backbone of thepolypeptide.

By “internal site” as used in referenced to a polypeptide or an aminoacid sequence of a polypeptide means a region of the polypeptide that isnot at the N-terminus or at the C-terminus.

Before the present invention is further described, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present invention will be limited only by the appendedclaims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges, and are also encompassed within the invention, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the invention.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable sub-combination. All combinations of the embodimentspertaining to the invention are specifically embraced by the presentinvention and are disclosed herein just as if each and every combinationwas individually and explicitly disclosed, to the extent that suchcombinations embrace subject matter that are, for example, compoundsthat are stable compounds (i.e., compounds that can be made, isolated,characterized, and tested for biological activity). In addition, allsub-combinations of the various embodiments and elements thereof (e.g.,elements of the chemical groups listed in the embodiments describingsuch variables) are also specifically embraced by the present inventionand are disclosed herein just as if each and every such sub-combinationwas individually and explicitly disclosed herein.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, the preferredmethods and materials are now described. All publications mentionedherein are incorporated herein by reference to disclose and describe themethods and/or materials in connection with which the publications arecited.

It must be noted that as used herein and in the appended claims, thesingular forms “a,” “an,” and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “analdehyde-tagged Ig polypeptide” includes a plurality of suchpolypeptides and reference to “the drug-conjugated Ig polypeptide”includes reference to one or more drug-conjugated Ig polypeptide andequivalents thereof known to those skilled in the art, and so forth. Itis further noted that the claims may be drafted to exclude any optionalelement. As such, this statement is intended to serve as antecedentbasis for use of such exclusive terminology as “solely,” “only” and thelike in connection with the recitation of claim elements, or use of a“negative” limitation.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable sub-combination.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present invention isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

DETAILED DESCRIPTION

The present disclosure provides aldehyde-tagged immunoglobulin (Ig)polypeptides that can be converted by a formylglycine-generating enzyme(FGE) to produce a formylglycine (FGly)-modified Ig polypeptide. AnFGly-modified Ig polypeptide can be covalently and site-specificallybound to a moiety of interest via reaction with an aldehyde-reactivereactive partner to provide an Ig conjugate. The disclosure alsoencompasses methods of production of such aldehyde-tagged Igpolypeptides, FGly-modified Ig polypeptides, and Ig conjugates, as wellas methods of use of same.

Aldehyde-tagged Ig polypeptides may also be referred to herein as“ald-tagged Ig polypeptides”, “ald-tagged Ig heavy chains” or“ald-tagged Ig light chains”. Such Ald-tagged Ig polypeptides can besite-specifically decorated with a covalently bound molecule ofinterest, such as a drug (e.g., a peptide drug, a small molecule drug,and the like), a water-soluble polymer, a detectable label, a syntheticpeptide, etc.

The compositions and methods of the present disclosure exploit anaturally-occurring, genetically-encodable sulfatase motif for use as atag, referred to herein as an “aldehyde tag” or “ald tag”, to directsite-specific modification of the Ig polypeptide. The sulfatase motif ofthe aldehyde tag, which is based on a motif found in active sites ofsulfatases, contains a serine or cysteine residue that is capable ofbeing converted (oxidized) to a 2-formylglycine (FGly) residue by actionof a formylglycine generating enzyme (FGE) either in vivo (e.g., at thetime of translation of an ald tag-containing protein in a cell) or invitro (e.g., by contacting an ald tag-containing protein with an FGE ina cell-free system). The aldehyde moiety of the resulting FGly residuecan be used as a “chemical handle” to facilitate site-specific chemicalmodification of the Ig polypeptide, and thus site-specific attachment ofa moiety of interest. For example, a peptide modified to contain anα-nucleophile-containing moiety (e.g., an aminooxy or hydrazide moiety)can be reacted with the FGly-containing Ig polypeptide to yield aconjugate in which the Ig polypeptide and the peptide are linked by ahydrazone or oxime bond, respectively, or via alternativealdehyde-specific chemistries such as reductive amination. Thereactivity of the aldehyde thus allows for bioorthogonal andchemoselective modification of the Ig polypeptide, and thus provides asite-specific means for chemical modification that in turn can beexploited to provide for site-specific attachment of a moiety ofinterest in the final conjugate.

Aldehyde Tagged Immunoglobulin Polypeptides

The present disclosure provides isolated aldehyde-tagged Igpolypeptides, including aldehyde-tagged Ig heavy chains andaldehyde-tagged Ig light chains, where the aldehyde-tagged Igpolypeptides, where the aldehyde tag is within or adjacent asolvent-accessible loop region of the Ig constant region, and where thealdehyde tag is not at the C-terminus of the Ig polypeptide.

In general, an aldehyde tag can be based on any amino acid sequencederived from a sulfatase motif (also referred to as a “sulfatasedomain”) which is capable of being converted by action of aformylglycine generating enzyme (FGE) to contain a formylglycine (FGly).Such sulfatase motifs may also be referred to herein as anFGE-modification site. Action of FGE is directed in a sequence-specificmanner in that the FGE acts at a sulfatase motif positioned within theimmunoglobulin polypeptide.

The present disclosure also provides a library of aldehyde-tagged Igpolypeptides, where the library comprises a plurality (a population) ofmembers, and where each member Ig polypeptide comprises an aldehyde tagat a different location(s) from the other members.

The present disclosure provides an aldehyde-tagged antibody, where analdehyde-tagged antibody can include: 1) an aldehyde-tagged Ig heavychain constant region; and an aldehyde-tagged Ig light chain constantregion; 2) an aldehyde-tagged Ig heavy chain constant region; and an Iglight chain constant region that is not aldehyde tagged; or 3) an Igheavy chain constant region that is not aldehyde tagged; and analdehyde-tagged Ig light chain constant region. A subjectaldehyde-tagged antibody also includes VH and/or VL domains and can bindantigen.

Exemplary Aldehyde Tags

A minimal sulfatase motif of an aldehyde tag is usually 5 or 6 aminoacid residues in length, usually no more than 6 amino acid residues inlength. Sulfatase motifs provided in an Ig polypeptide are at least 5 or6 amino acid residues, and can be, for example, from 5 to 16, 6-16,5-15, 6-15, 5-14, 6-14, 5-13, 6-13, 5-12, 6-12, 5-11, 6-11, 5-10, 6-10,5-9, 6-9, 5-8, or 6-8 amino acid residues in length, so as to define asulfatase motif of less than 16, 15, 14, 13, 12, 11, 10, 9, 8 or 7 aminoacid residues in length.

In general, it is normally desirable to minimize the extent ofmodification of the native amino acid sequence of the target Igpolypeptide, so as to minimize the number of amino acid residues thatare inserted, deleted, substituted (replaced), or added (e.g., to the N-or C-terminus). Minimizing the extent of amino acid sequencemodification of the target Ig polypeptide is usually desirable so as tominimize the impact such modifications may have upon Ig function and/orstructure. Thus, aldehyde tags of particular interest include those thatrequire modification (insertion, addition, deletion,substitution/replacement) of less than 16, 15, 14, 13, 12, 11, 10, 9, 8,7, 6, 5, 4, 3 or 2 amino acid residues of the amino acid sequence of thetarget polypeptide. Where an amino acid sequence native to the Igpolypeptide contains one or more residues of the desired sulfatasemotif, the total number of modifications of residues can be reduced,e.g., by site-specification modification of amino acid residues flankingnative amino acid residues to provides a sequence of a sulfatase motif.

It should be noted that while aldehyde tags of particular interest arethose comprising at least a minimal sulfatase motif (also referred to a“consensus sulfatase motif”), it will be readily appreciated that longeraldehyde tags are both contemplated and encompassed by the presentdisclosure and can find use in the compositions and methods of theinvention. Aldehyde tags can thus comprise a minimal sulfatase motif of5 or 6 residues, or can be longer and comprise a minimal sulfatase motifwhich can be flanked at the N- and/or C-terminal sides of the motif byadditional amino acid residues. Aldehyde tags of, for example, 5 or 6amino acid residues are contemplated, as well as longer amino acidsequences of more than 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19, 20 or more amino acid residues.

In certain embodiments, the sulfatase motif used may be described by theformula:X₁Z₁X₂Z₂X₃Z₃ (SEQ ID NO: 283)  (I)

where

Z₁ is cysteine or serine (which can also be represented by (C/S));

Z₂ is either a proline or alanine residue (which can also be representedby (P/A));

Z₃ is a basic amino acid (e.g., arginine (R), and may be lysine (K) orhistidine (H), usually lysine), or an aliphatic amino acid (alanine (A),glycine (G), leucine (L), valine (V), isoleucine (I), or proline (P),usually A, G, L, V, or I;

X₁ is present or absent and, when present, can be any amino acid, thoughusually an aliphatic amino acid, a sulfur-containing amino acid, or apolar, uncharged amino acid, (i.e., other than a aromatic amino acid ora charged amino acid), usually L, M, V, S or T, more usually L, M, S orV, with the proviso that when the sulfatase motif is at the N-terminusof the target polypeptide, X₁ is present; and

X₂ and X₃ independently can be any amino acid, though usually analiphatic amino acid, a polar, uncharged amino acid, or a sulfurcontaining amino acid (i.e., other than a aromatic amino acid or acharged amino acid), usually S, T, A, V, G or C, more usually S, T, A, Vor G.

Thus, the present disclosure provides isolated aldehyde-tagged Igpolypeptides, including aldehyde-tagged Ig heavy chains andaldehyde-tagged Ig light chains, where the aldehyde-tagged Igpolypeptides comprise an Ig constant region amino acid sequence modifiedto provide a sequence of at least 5 amino acids of the formulaX₁Z₁X₂Z₂X₃Z₃ (SEQ ID NO: 283), where

Z₁ is cysteine or serine;

Z₂ is a proline or alanine residue;

Z₃ is an aliphatic amino acid or a basic amino acid;

X₁ is present or absent and, when present, is any amino acid, with theproviso that when the heterologous sulfatase motif is at an N-terminusof the polypeptide, X₁ is present;

X₂ and X₃ are each independently any amino acid,

where the sequence is within or adjacent a solvent-accessible loopregion of the Ig constant region, and wherein the sequence is not at theC-terminus of the Ig heavy chain.

It should be noted that, following action of an FGE on the sulfatasemotif, Z₁ is oxidized to generate a formylglycine (FGly) residue.Furthermore, following both FGE-mediated conversion and reaction with areactive partner comprising a moiety of interest, FGly position at Z₁ inthe formula above is covalently bound to the moiety of interest (e.g.,detectable label, water soluble polymer, polypeptide, drug, etc).

Where the aldehyde tag is present at a location other than theN-terminus of the target polypeptide, X₁ of the formula above can beprovided by an amino acid residue of the native amino acid sequence ofthe target polypeptide. Therefore, in some embodiments, and when presentat a location other than the N-terminus of a target polypeptide,sulfatase motifs are of the formula:(C/S)X₁(P/A)X₂Z₃ (SEQ ID NO: 284)  (II)

where X₁ and X₂ independently can be any amino acid, though usually analiphatic amino acid, a polar, uncharged amino acid, or asulfur-containing amino acid (i.e., other than an aromatic amino acid ora charged amino acid), usually S, T, A, V, or C, more usually S, T, A,or V; and Z₃ is a basic amino acid (e.g., arginine (R), and may belysine (K) or histidine (H), usually lysine), or an aliphatic amino acid(alanine (A), glycine (G), leucine (L), valine (V), isoleucine (I), orproline (P), usually A, G, L, V, or I.

As noted above, the sulfatase motif can contain additional residues atone or both of the N- and C-terminus of the sequence, e.g., such thatthe aldehyde tag includes both a sulfatase motif and an “auxiliarymotif”. In one embodiment, the sulfatase motif includes an auxiliarymotif at the C-terminus (i.e., following the arginine residue in theformula above) 1, 2, 3, 4, 5, 6, or all 7 of the contiguous residues ofan amino acid sequence of AALLTGR (SEQ ID NO:92), SQLLTGR (SEQ IDNO:93), AAFMTGR (SEQ ID NO:94), AAFLTGR (SEQ ID NO:95), SAFLTGR (SEQ IDNO:96), ASILTGK (SEQ ID NO:97), VSFLTGR (SEQ ID NO:98), ASLLTGL (SEQ IDNO:99), ASILITG (SEQ ID NO:100), VSFLTGR (SEQ ID NO:101), SAIMTGR (SEQID NO:102), SAIVTGR (SEQ ID NO:103), TNLWRG (SEQ ID NO:104), TNLWRGQ(SEQ ID NO:105), TNLCAAS (SEQ ID NO:106), VSLWTGK (SEQ ID NO:107),SMLLTG (SEQ ID NO:108), SMLLTGN (SEQ ID NO:109), SMLLTGT (SEQ IDNO:110), ASFMAGQ (SEQ ID NO:111), or ASLLTGL (SEQ ID NO:112), (see,e.g., Dierks et al. (1999) EMBO J 18(8): 2084-2091), or of GSLFTGR (SEQID NO:113). However, such additional C-terminal amino acid residues arenot required for FGE-mediated conversion of the sulfatase motif of thealdehyde tag, and thus are only optional and may be specificallyexcluded from the aldehyde tags described herein. In some embodimentsthe aldehyde tag does not contain an amino acid sequence CGPSR(M/A)S(SEQ ID NO:114) or CGPSR(M/A) (SEQ ID NO:115), which may be present as anative amino acid sequence in phosphonate monoester hydrolases.

The sulfatase motif of the aldehyde tag is generally selected so as tobe capable of conversion by a selected FGE, e.g., an FGE present in ahost cell in which the aldehyde tagged polypeptide is expressed or anFGE which is to be contacted with the aldehyde tagged polypeptide in acell-free in vitro method.

Selection of aldehyde tags and an FGE that provide for suitable reactivepartners to provide for generation of an FGly in the aldehyde taggedtarget Ig polypeptide can be readily accomplished in light ofinformation available in the art. In general, sulfatase motifssusceptible to conversion by a eukaryotic FGE contain a cysteine and aproline (i.e., a cysteine and proline at Z₁ and Z₂, respectively, inFormula I above (e.g., X₁CX₂PX₃Z₃ (SEQ ID NO: 285)); CX₁PX₂Z₃ (SEQ IDNO: 286) in Formula II above) and are modified by the “SUMF1-type” FGE(Cosma et al. Cell 2003, 113, (4), 445-56; Dierks et al. Cell 2003, 113,(4), 435-44). Sulfatase motifs susceptible to conversion by aprokaryotic FGE contain either a cysteine or a serine, and a proline inthe sulfatase motif (i.e., a cysteine or serine at Z₁, and a proline atZ₂, respectively, in Formula I above (e.g., X₁(C/S)X₂PX₃Z₃ (SEQ ID NO:287)); (C/S)X₁PX₂Z₃ (SEQ ID NO: 288) in Formula II above) are modifiedeither by the “SUMF1-type” FGE or the “AtsB-type” FGE, respectively(Szameit et al. J Biol Chem 1999, 274, (22), 15375-81). Other sulfatasemotifs susceptible to conversion by a prokaryotic FGE contain either acysteine or a serine, and either a proline or an alanine in thesulfatase motif (i.e., a cysteine or serine at Z₁, and a proline oralanine at Z₂, respectively, in Formula I or II above (e.g., X₁CX₂PX₃R(SEQ ID NO: 289); X₁SX₂PX₂R (SEQ ID NO: 290); X₁CX₂AX₃R (SEQ ID NO:291); X₁SX₂AX₃R (SEQ ID NO: 292); CX₁PX₂R (SEQ ID NO: 293); SX₁PX₂R (SEQID NO: 294); CX₁AX₂R (SEQ ID NO: 295); SX₁AX₂R (SEQ ID NO: 296),X₁CX₂PX₃Z₃ (SEQ ID NO: 285); X₁SX₂PX₂Z₃ (SEQ ID NO: 297); X₁CX₂AX₃Z₃(SEQ ID NO: 298); X₁SX₂AX₃Z₃(SEQ ID NO: 299); CX₁PX₂Z₃ (SEQ ID NO: 286);SX₁PX₂Z₃ (SEQ ID NO: 300); CX₁AX₂Z₃ (SEQ ID NO: 301); SX₁AX₂Z₃ (SEQ IDNO: 302)), and are susceptible to modification by, for example, can bemodified by an FGE of a Firmicutes (e.g., Clostridium perfringens) (seeBerteau et al. J. Biol. Chem. 2006; 281:22464-22470) or an FGE ofMycobacterium tuberculosis.

Therefore, for example, where the FGE is a eukaryotic FGE (e.g., amammalian FGE, including a human FGE), the sulfatase motif is usually ofthe formula:X₁CX₂PX₃Z₃  (SEQ ID NO: 285)

where

X₁ may be present or absent and, when present, can be any amino acid,though usually an aliphatic amino acid, a sulfur-containing amino acid,or a polar, uncharged amino acid, (i.e., other than a aromatic aminoacid or a charged amino acid), usually L, M, S or V, with the provisothat when the sulfatase motif is at the N-terminus of the targetpolypeptide, X₁ is present;

X₂ and X₃ independently can be any amino acid, though usually analiphatic amino acid, a sulfur-containing amino acid, or a polar,uncharged amino acid, (i.e., other than a aromatic amino acid or acharged amino acid), usually S, T, A, V, G, or C, more usually S, T, A,V or G; and

Z₃ is a basic amino acid (e.g., arginine (R), and may be lysine (K) orhistidine (H), usually lysine), or an aliphatic amino acid (alanine (A),glycine (G), leucine (L), valine (V), isoleucine (I), or proline (P),usually A, G, L, V, or I.

Specific examples of sulfatase motifs include LCTPSR (SEQ ID NO:17),MCTPSR (SEQ ID NO:116), VCTPSR (SEQ ID NO:117), LCSPSR (SEQ ID NO:118),LCAPSR (SEQ ID NO:119), LCVPSR (SEQ ID NO:120), LCGPSR (SEQ ID NO:121),ICTPAR (SEQ ID NO:122), LCTPSK (SEQ ID NO:123), MCTPSK (SEQ ID NO:124),VCTPSK (SEQ ID NO:125), LCSPSK (SEQ ID NO:126), LCAPSK (SEQ ID NO:127),LCVPSK (SEQ ID NO:128), LCGPSK (SEQ ID NO:129), LCTPSA (SEQ ID NO:130),ICTPAA (SEQ ID NO:131), MCTPSA (SEQ ID NO:132), VCTPSA (SEQ ID NO:133),LCSPSA (SEQ ID NO:134), LCAPSA (SEQ ID NO:135), LCVPSA (SEQ ID NO:136),and LCGPSA (SEQ ID NO:137). Other specific sulfatase motifs are readilyapparent from the disclosure provided herein.

Formylglycine-Modified Ig Polypeptides

As described in more detail below, a converted aldehyde tagged Igpolypeptide is reacted with a reactive partner containing a moiety ofinterest to provide for conjugation of the moiety of interest to theFGly residue of the converted aldehyde tagged Ig polypeptide, andproduction of a modified polypeptide. Modified Ig polypeptides having amodified aldehyde tag are generally described by comprising a modifiedsulfatase motif of the formula:X₁(FGly′)X₂Z₂X₃Z₃ (SEQ ID NO: 303)  (I′)

where

FGly′ is the formylglycine residue having a covalently attached moiety;

Z₂ is either a proline or alanine residue (which can also be representedby (P/A)); Z₃ is a basic amino acid (e.g., arginine (R), and may belysine (K) or histidine (H), usually lysine), or an aliphatic amino acid(alanine (A), glycine (G), leucine (L), valine (V), isoleucine (I), orproline (P), usually A, G, L, V, or I;

X₁ may be present or absent and, when present, can be any amino acid,though usually an aliphatic amino acid, a sulfur-containing amino acid,or a polar, uncharged amino acid, (i.e., other than a aromatic aminoacid or a charged amino acid), usually L, M, V, S or T, more usually L,M or V, with the proviso that when the sulfatase motif is at theN-terminus of the target polypeptide, X₁ is present; and

X₂ and X₃ independently can be any amino acid, though usually analiphatic amino acid, a sulfur-containing amino acid, or a polar,uncharged amino acid, (i.e., other than a aromatic amino acid or acharged amino acid), usually S, T, A, V, G or C, more usually S, T, A, Vor G.

Thus, the present disclosure provides an Ig polypeptide modified tocomprise formylglycine moiety, wherein the Ig polypeptide comprises anFGly-converted sulfatase motif of the formula:X₁(FGly)X₂Z₂X₃Z₃  (SEQ ID NO: 304)

wherein:

X₁ is present or absent and, when present, is any amino acid, with theproviso that when the sulfatase motif is at an N-terminus of thepolypeptide, X₁ is present;

X₂ and X₃ are each independently any amino acid; and

Z³ is a basic amino acid; and

where the FGly-modified Ig polypeptide presents the FGly group on asolvent-accessible surface when in a folded state.

The present disclosure also provides a library of FGly-modified Igpolypeptides, where the library comprises a plurality (a population) ofmembers, where each member FGly-modified Ig polypeptide comprises anFGly-modified aldehyde tag, and where each member FGly-modified Igpolypeptide comprises an aldehyde tag at a different location(s) fromthe other members. FIG. 2 depicts an example of a scheme for generatinga library of FGly-modified Ig polypeptides, in which each member Igpolypeptide comprises an aldehyde tag at a different location from theother members. FIG. 2 depicts attachment of drug to the FGly-modifiedpolypeptides.

The present disclosure provides an FGly-modified antibody, where anFGly-modified antibody can include: 1) an FGly-modified Ig heavy chainconstant region; and an FGly-modified Ig light chain constant region; 2)an FGly-modified Ig heavy chain constant region; and an Ig light chainconstant region that is not FGly-modified; or 3) an Ig heavy chainconstant region that is not FGly-modified; and an FGly-modified Ig lightchain constant region. A subject FGly-modified antibody also includes VHand/or VL domains and can bind antigen.

Specific examples of converted sulfatase motifs include L(FGly)TPSR (SEQID NO:138), M(FGly)TPSR (SEQ ID NO:139), V(FGly)TPSR (SEQ ID NO:140),L(FGly)SPSR (SEQ ID NO:141), L(FGly)APSR (SEQ ID NO:142), L(FGly)VPSR(SEQ ID NO:143), and L(FGly)GPSR (SEQ ID NO:144), I(FGly)TPAR (SEQ IDNO:145), L(FGly)TPSK (SEQ ID NO:146), M(FGly)TPSK (SEQ ID NO:147),V(FGly)TPSK (SEQ ID NO:148), L(FGly)SPSK (SEQ ID NO:149), L(FGly)APSK(SEQ ID NO:150), L(FGly)VPSK (SEQ ID NO:151), L(FGly)GPSK (SEQ IDNO:152), L(FGly)TPSA (SEQ ID NO:152), M(FGly)TPSA (SEQ ID NO:153),V(FGly)TPSA (SEQ ID NO:154), L(FGly)SPSA (SEQ ID NO:155), L(FGly)APSA(SEQ ID NO:156), L(FGly)VPSA (SEQ ID NO:157), and L(FGly)GPSA (SEQ IDNO:158).

As described in more detail below, the moiety of interest can be any ofa variety of moieties such as a water-soluble polymer, a detectablelabel, a drug, or a moiety for immobilization of the Ig polypeptide in amembrane or on a surface. As is evident from the above discussion ofaldehyde tagged Ig polypeptides, the modified sulfatase motif of themodified polypeptide can be positioned at any desired site of thepolypeptide. Thus, the present disclosure provides, for example, amodified polypeptide having a modified sulfatase motif positioned at asite of post-translational modification of a parent of the modifiedpolypeptide (i.e., if the target polypeptide is modified to provide analdehyde tag at a site of post-translational modification, thelater-produced modified polypeptide will contain a moiety at a positioncorresponding to this site of post-translational modification in theparent polypeptide). For example, then, a modified polypeptide can beproduced so as to have a covalently bound, water-soluble polymer at asite corresponding to a site at which glycosylation would normally occurin the parent target polypeptide. Thus, for example, a PEGylatedpolypeptide can be produced having the PEG moiety positioned at the sameor nearly the same location as sugar residues would be positioned in thenaturally-occurring parent polypeptide. Similarly, where the parenttarget polypeptide is engineered to include one or more non-native sitesof post-translational modification, the modified polypeptide can containcovalently attached water-soluble polymers at one or more sites of themodified polypeptide corresponding to these non-native sites ofpost-translational modification in the parent polypeptide.

Modification of a Target Ig Polypeptide to Include an Aldehyde Tag

Modification of a target Ig polypeptide to include one or more aldehydetags can be accomplished using recombinant molecular genetic techniques,so as produce nucleic acid encoding the desired aldehyde tagged Igpolypeptide. Such methods are well known in the art, and include cloningmethods, site-specific mutation methods, and the like (see, e.g.,Sambrook et al., In “Molecular Cloning: A Laboratory Manual” (ColdSpring Harbor Laboratory Press 1989); “Current Protocols in MolecularBiology” (eds., Ausubel et al.; Greene Publishing Associates, Inc., andJohn Wiley & Sons, Inc. 1990 and supplements).

Target Immunoglobulin Heavy and Light Chains

As discussed above, the present disclosure provides aldehyde-tagged Igpolypeptides, FGly-modified aldehyde-tagged Ig polypeptides, and Igconjugates. The Ig polypeptides used to generate an aldehyde-tagged Igpolypeptide, an FGly-modified aldehyde-tagged Ig polypeptide, or an Igconjugate, of the present disclosure, include at least an Ig constantregion, e.g., an Ig heavy chain constant region (e.g., at least a CH1domain; at least a CH1 and a CH2 domain; a CH1, a CH2, and a CH3 domain;or a CH1, a CH2, a CH3, and a CH4 domain), or an Ig light chain constantregion. Such Ig polypeptides are referred to herein as “target Igpolypeptides.”

A target Ig polypeptide can comprise an amino acid sequence having 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, amino acidsequence identity to a contiguous stretch of from about 300 amino acidsto about 330 amino acids of an amino acid sequence of a heavy chainconstant region depicted in FIG. 1B. For example, a target Igpolypeptide can comprise an amino acid sequence having 90%, 91%, 92%,93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, amino acid sequence identityto a contiguous stretch of from about 300 amino acids to about 330 aminoacids of the amino acid sequence set forth in SEQ ID NO:2.

A target Ig polypeptide can comprise an amino acid sequence having 90%,91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, amino acidsequence identity to a contiguous stretch of from about 200 amino acidsto about 233 amino acids, or from about 200 amino acids to about 236amino acids, of an amino acid sequence of a light chain constant regiondepicted in FIG. 1C. For example, a target Ig polypeptide can comprisean amino acid sequence having 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%,98%, 99%, or 100%, amino acid sequence identity to a contiguous stretchof from about 200 amino acids to about 236 amino acids of the amino acidsequence set forth in SEQ ID NO:1.

As noted above, a target Ig polypeptide generally includes at least anIg heavy chain constant region or an Ig light chain constant region, andcan further include an Ig variable region (e.g., a V_(L) region and/or aV_(H) region). Ig heavy chain constant regions include Ig constantregions of any heavy chain isotype, non-naturally occurring Ig heavychain constant regions (including consensus Ig heavy chain constantregions). An Ig constant region can be modified to include an aldehydetag, where the aldehyde tag is present in or adjacent asolvent-accessible loop region of the Ig constant region.

An Ig constant region can be modified by insertion and/or substitutionof 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16 amino acids,or more than 16 amino acids, to provide an amino acid sequence of asulfatase motif as described above.

In some cases, an aldehyde-tagged Ig polypeptide of the presentdisclosure comprises an aldehyde-tagged Ig heavy chain constant region(e.g., at least a CH1 domain; at least a CH1 and a CH2 domain; a CH1, aCH2, and a CH3 domain; or a CH1, a CH2, a CH3, and a CH4 domain). Thealdehyde-tagged Ig heavy chain constant region can include heavy chainconstant region sequences of an IgA, IgM, IgD, IgE, IgG1, IgG2, IgG3, orIgG4 isotype heavy chain or any allotypic variant of same, e.g., humanheavy chain constant region sequences or mouse heavy chain constantregion sequences, a hybrid heavy chain constant region, a syntheticheavy chain constant region, or a consensus heavy chain constant regionsequence, etc., modified to include at least one sulfatase motif thatcan be modified by an FGE to generate an FGly-modified Ig polypeptide.Allotypic variants of Ig heavy chains are known in the art. See, e.g.,Jefferis and Lefranc (2009) MAbs 1:4.

In some cases, an aldehyde-tagged Ig polypeptide of the presentdisclosure comprises an aldehyde-tagged Ig light chain constant region.The aldehyde-tagged Ig light chain constant region can include constantregion sequences of a kappa light chain, a lambda light chain, e.g.,human kappa or lambda light chain constant regions, a hybrid light chainconstant region, a synthetic light chain constant region, or a consensuslight chain constant region sequence, etc., modified to include at leastone sulfatase motif that can be modified by an FGE to generate anFGly-modified Ig polypeptide. Exemplary constant regions include humangamma 1 and gamma 3 regions. With the exception of the sufatase motif, amodified constant region may have a wild-type amino acid sequence, or itmay have an amino acid sequence that is at least 70% identical (e.g., atleast 80%, at least 90% or at least 95% identical) to a wild type aminoacid sequence.

As noted above, an isolated aldehyde-tagged Ig polypeptide of thepresent disclosure comprises an Ig constant region amino acid sequencemodified to provide a sulfatase motif sequence of at least 5 amino acidsof the formula described above, where the sequence is within or adjacenta solvent-accessible loop region of the Ig polypeptide constant region.In some embodiments the sulfatase motif is at a position other than, orin addition to, the C-terminus of the Ig polypeptide heavy chain.

Solvent accessible loop of an antibody can be identified by molecularmodeling, or by comparison to a known antibody structure. The relativeaccessibility of amino acid residues can also be calculated using amethod of DSSP (Dictionary of Secondary Structure in Proteins; Kabschand Sander 1983 Biopolymers 22: 2577-637) and solvent accessible surfacearea of an amino acid may be calculated based on a 3-dimensional modelof an antibody, using algorithms known in the art (e.g., Connolly, J.Appl. Cryst. 16, 548 (1983) and Lee and Richards, J. Mol. Biol. 55, 379(1971), both of which are incorporated herein by reference).

As noted above, an isolated aldehyde-tagged Ig polypeptide can comprisea heavy chain constant region modified to include a sulfatase motif asdescribed above, where the sulfatase motif is in or adjacent asurface-accessible loop region of the Ig polypeptide heavy chainconstant region. Illustrative examples of surface-accessible loopregions of a heavy chain constant region are presented in FIGS. 1A and1B.

In some instances, a target immunoglobulin is modified to include asulfatase motif as described above, where the sulfatase motif is within,or adjacent to, a region of an IgG1 heavy chain constant regioncorresponding to one or more of: 1) amino acids 122-127; 2) amino acids137-143; 3) amino acids 155-158; 4) amino acids 163-170; 5) amino acids163-183; 6) amino acids 179-183; 7) amino acids 190-192; 8) amino acids200-202; 9) amino acids 199-202; 10) amino acids 208-212; 11) aminoacids 220-241; 12) amino acids 247-251; 13) amino acids 257-261; 14)amino acid 269-277; 15) amino acids 271-277; 16) amino acids 284-285;17) amino acids 284-292; 18) amino acids 289-291; 19) amino acids299-303; 20) amino acids 309-313; 21) amino acids 320-322; 22) aminoacids 329-335; 23) amino acids 341-349; 24) amino acids 342-348; 25)amino acids 356-365; 26) amino acids 377-381; 27) amino acids 388-394;28) amino acids 398-407; 29) amino acids 433-451; and 30) amino acids446-451; wherein the amino acid numbering is based on the amino acidnumbering of human IgG1 as depicted in FIG. 1B.

Exemplary surface-accessible loop regions of an IgG1 heavy chaininclude: 1) ASTKGP (SEQ ID NO:71); 2) KSTSGGT (SEQ ID NO:72); 3) PEPV(SEQ ID NO:73); 4) NSGALTSG (SEQ ID NO:202); 5) NSGALTSGVHTFPAVLQSSGL(SEQ ID NO:74); 6) QSSGL (SEQ ID NO:227); 7) VTV; 8) QTY; 9) TQTY (SEQID NO:75); 10) HKPSN (SEQ ID NO:76); 11) EPKSCDKTHTCPPCPAPELLGG (SEQ IDNO:77); 12) FPPKP (SEQ ID NO:78); 13) ISRTP (SEQ ID NO:79); 14)DVSHEDPEV (SEQ ID NO:80); 15) SHEDPEV (SEQ ID NO:223; 16) DG; 17)DGVEVHNAK (SEQ ID NO:81); 18) HNA; 19) QYNST (SEQ ID NO:82); 20) VLTVL(SEQ ID NO:83); 21) GKE; 22) NKALPAP (SEQ ID NO:84); 23) SKAKGQPRE (SEQID NO:85); 24) KAKGQPR (SEQ ID NO:206); 25) PPSRKELTKN (SEQ ID NO:86);26) YPSDI (SEQ ID NO:87); 27) NGQPENN (SEQ ID NO:88); 28) TPPVLDSDGS(SEQ ID NO:89); 29) HEALHNHYTQKSLSLSPGK (SEQ ID NO:90); and 30) SLSPGK(SEQ ID NO:175), as shown in FIGS. 1A and 1B.

In some instances, a target immunoglobulin is modified to include asulfatase motif as described above, where the sulfatase motif is within,or adjacent to, a region of an IgG2 heavy chain constant regioncorresponding to one or more of: 1) amino acids 1-6; 2) amino acids13-24; 3) amino acids 33-37; 4) amino acids 43-54; 5) amino acids 58-63;6) amino acids 69-71; 7) amino acids 78-80; 8) 87-89; 9) amino acids95-96; 10) 114-118; 11) 122-126; 12) 134-136; 13) 144-152; 14) 159-167;15) 175-176; 16) 184-188; 17) 195-197; 18) 204-210; 19) 216-224; 20)231-233; 21) 237-241; 22) 252-256; 23) 263-269; 24) 273-282; 25) aminoacids 299-302; where the amino acid numbering is based on the numberingof the amino acid sequence set forth in SEQ ID NO:4 (human IgG2; alsodepicted in FIG. 1B).

Exemplary surface-accessible loop regions of an IgG2 heavy chaininclude 1) ASTKGP (SEQ ID NO:71); 2) PCSRSTSESTAA (SEQ ID NO:91); 3)FPEPV (SEQ ID NO:168); 4) SGALTSGVHTFP (SEQ ID NO:159); 5) QSSGLY (SEQID NO:160); 6) VTV; 7) TQT; 8) HKP; 9) DK; 10) VAGPS (SEQ ID NO:161);11) FPPKP (SEQ ID NO:78); 12) RTP; 13) DVSHEDPEV (SEQ ID NO:80); 14)DGVEVHNAK (SEQ ID NO:81); 15) FN; 16) VLTVV (SEQ ID NO:162); 17) GKE;18) NKGLPAP (SEQ ID NO:163); 19) SKTKGQPRE (SEQ ID NO:164); 20) PPS; 21)MTKNQ (SEQ ID NO:165); 22) YPSDI (SEQ ID NO:87); 23) NGQPENN (SEQ IDNO:88); 24) TPPMLDSDGS (SEQ ID NO:166); 25) GNVF (SEQ ID NO:182); and26) HEALHNHYTQKSLSLSPGK (SEQ ID NO:90), as shown in FIG. 1B.

In some instances, a target immunoglobulin is modified to include asulfatase motif as described above, where the sulfatase motif is within,or adjacent to, a region of an IgG3 heavy chain constant regioncorresponding to one or more of: 1) amino acids 1-6; 2) amino acids13-22; 3) amino acids 33-37; 4) amino acids 43-61; 5) amino acid 71; 6)amino acids 78-80; 7) 87-91; 8) amino acids 97-106; 9) 111-115; 10)147-167; 11) 173-177; 16) 185-187; 13) 195-203; 14) 210-218; 15)226-227; 16) 238-239; 17) 246-248; 18) 255-261; 19) 267-275; 20)282-291; 21) amino acids 303-307; 22) amino acids 313-320; 23) aminoacids 324-333; 24) amino acids 350-352; 25) amino acids 359-365; and 26)amino acids 372-377; where the amino acid numbering is based on thenumbering of the amino acid sequence set forth in SEQ ID NO:3 (humanIgG3; also depicted in FIG. 1B).

Exemplary surface-accessible loop regions of an IgG3 heavy chaininclude 1) ASTKGP (SEQ ID NO:71); 2) PCSRSTSGGT (SEQ ID NO:167); 3)FPEPV (SEQ ID NO:168); 4) SGALTSGVHTFPAVLQSSG (SEQ ID NO:169); 5) V; 6)TQT; 7) HKPSN (SEQ ID NO:76); 8) RVELKTPLGD (SEQ ID NO:170); 9) CPRCPKP(SEQ ID NO:171); 10) PKSCDTPPPCPRCPAPELLGG (SEQ ID NO:229); 11) FPPKP(SEQ ID NO:78); 12) RTP; 13) DVSHEDPEV (SEQ ID NO:80); 14) DGVEVHNAK(SEQ ID NO:81); 15) YN; 16) VL; 17) GKE; 18) NKALPAP (SEQ ID NO:84); 19)SKTKGQPRE (SEQ ID NO:164); 20) PPSREEMTKN (SEQ ID NO:172); 21) YPSDI(SEQ ID NO:87); 22) SSGQPENN (SEQ ID NO:173); 23) TPPMLDSDGS (SEQ IDNO:166); 24) GNI; 25) HEALHNR (SEQ ID NO:174); and 26) SLSPGK (SEQ IDNO:175), as shown in FIG. 1B.

In some instances, a target immunoglobulin is modified to include asulfatase motif as described above, where the sulfatase motif is within,or adjacent to, a region of an IgG4 heavy chain constant regioncorresponding to one or more of: 1) amino acids 1-5; 2) amino acids12-23; 3) amino acids 32-36; 4) amino acids 42-53; 5) amino acids 57-62;6) amino acids 68-70; 7) amino acids 77-79; 8) amino acids 86-88; 9)amino acids 94-95; 10) amino acids 101-102; 11) amino acids 108-118; 12)amino acids 122-126; 13) amino acids 134-136; 14) amino acids 144-152;15) amino acids 159-167; 16) amino acids 175-176; 17) amino acids185-186; 18) amino acids 196-198; 19) amino acids 205-211; 20) aminoacids 217-226; 21) amino acids 232-241; 22) amino acids 253-257; 23)amino acids 264-265; 24) 269-270; 25) amino acids 274-283; 26) aminoacids 300-303; 27) amino acids 399-417; where the amino acid numberingis based on the numbering of the amino acid sequence set forth in SEQ IDNO:5 (human IgG4; also depicted in FIG. 1B).

Exemplary surface-accessible loop regions of an IgG4 heavy chaininclude 1) STKGP (SEQ ID NO:176); 2) PCSRSTSESTAA (SEQ ID NO:91); 3)FPEPV (SEQ ID NO:168); 4) SGALTSGVHTFP (SEQ ID NO:159); 5) QSSGLY (SEQID NO:160); 6) VTV; 7) TKT; 8) HKP; 9) DK; 10) YG; 11) CPAPEFLGGPS (SEQID NO:177); 12) FPPKP (SEQ ID NO:78); 13) RTP; 14) DVSQEDPEV (SEQ IDNO:178); 15) DGVEVHNAK (SEQ ID NO:81); 16) FN; 17) VL; 18) GKE; 19)NKGLPSS (SEQ ID NO:179); 20) SKAKGQPREP (SEQ ID NO:180); 21) PPSQEEMTKN(SEQ ID NO:181); 22) YPSDI (SEQ ID NO:87); 23) NG; 24) NN; 25)TPPVLDSDGS (SEQ ID NO:89); 26) GNVF (SEQ ID NO:182); and 27)HEALHNHYTQKSLSLSLGK (SEQ ID NO:183), as shown in FIG. 1B.

In some instances, a target immunoglobulin is modified to include asulfatase motif as described above, where the sulfatase motif is within,or adjacent to, a region of an IgA heavy chain constant regioncorresponding to one or more of: 1) amino acids 1-13; 2) amino acids17-21; 3) amino acids 28-32; 4) amino acids 44-54; 5) amino acids 60-66;6) amino acids 73-76; 7) amino acids 80-82; 8) amino acids 90-91; 9)amino acids 123-125; 10) amino acids 130-133; 11) amino acids 138-142;12) amino acids 151-158; 13) amino acids 165-174; 14) amino acids181-184; 15) amino acids 192-195; 16) amino acid 199; 17) amino acids209-210; 18) amino acids 222-245; 19) amino acids 252-256; 20) aminoacids 266-276; 21) amino acids 293-294; 22) amino acids 301-304; 23)amino acids 317-320; 24) amino acids 329-353; where the amino acidnumbering is based on the numbering of the amino acid sequence set forthin SEQ ID NO:6 (human IgA; also depicted in FIG. 1B).

Exemplary surface-accessible loop regions of an IgA heavy chaininclude 1) ASPTSPKVFPLSL (SEQ ID NO:184); 2) QPDGN (SEQ ID NO:185); 3)VQGFFPQEPL (SEQ ID NO:186); 4) SGQGVTARNFP (SEQ ID NO:187); 5) SGDLYTT(SEQ ID NO:188); 6) PATQ (SEQ ID NO:189); 7) GKS; 8) YT; 9) CHP; 10)HRPA (SEQ ID NO:190); 11) LLGSE (SEQ ID NO:191); 12) GLRDASGV (SEQ IDNO:192); 13) SSGKSAVQGP (SEQ ID NO:193); 14) GCYS (SEQ ID NO:194); 15)CAEP (SEQ ID NO:195); 16) PE; 17) SGNTFRPEVHLLPPPSEELALNEL (SEQ IDNO:196); 18) ARGFS (SEQ ID NO:197); 19) QGSQELPREKY (SEQ ID NO:198); 20)AV; 21) AAED (SEQ ID NO:199); 22) HEAL (SEQ ID NO:200); and 23)IDRLAGKPTHVNVSVVMAEVDGTCY (SEQ ID NO:201), as shown in FIG. 1B.

A sulfatase motif can be provided within or adjacent one or more ofthese amino acid sequences of such modification sites of an Ig heavychain. For example, an Ig heavy chain polypeptide can be modified at oneor more of these amino acid sequences to provide a sulfatase motifadjacent and N-terminal and/or adjacent and C-terminal to thesemodification sites. Alternatively or in addition, an Ig heavy chainpolypeptide can be modified at one or more of these amino acid sequencesto provide a sulfatase motif insertion between any two residues of theIg heavy chain modifications sites. In some embodiments, an Ig heavychain polypeptide may be modified to include two motifs, which may beadjacent to one another, or which may be separated by one, two, three,four or more (e.g., from about 1 to about 25, from about 25 to about 50,or from about 50 to about 100, or more, amino acids. Alternatively or inaddition, where a native amino acid sequence provides for one or moreamino acid residues of a sulfatase motif sequence, selected amino acidresidues of the modification sites of an Ig heavy chain polypeptideamino acid sequence can be modified so as to provide a sulfatase motifat the modification site.

The amino acid sequence of a surface-accessible loop region can thus bemodified to provide a sulfatase motif, where the modifications caninclude substitution and/or insertion. For example, where themodification is in a CH1 domain, the surface-accessible loop region canhave the amino acid sequence NSGALTSG (SEQ ID NO:202), and thealdehyde-tagged sequence can be, e.g., NSGALCTPSRG (SEQ ID NO:203),e.g., where the “TS” residues of the NSGALTSG (SEQ ID NO:202) sequenceare replaced with “CTPSR,” (SEQ ID NO:204) such that the sulfatase motifhas the sequence LCTPSR (SEQ ID NO:17). As another example, where themodification is in a CH2 domain, the surface-accessible loop region canhave the amino acid sequence NKALPAP (SEQ ID NO:84), and thealdehyde-tagged sequence can be, e.g., NLCTPSRAP (SEQ ID NO:205), e.g.,where the “KAL” residues of the NKALPAP (SEQ ID NO:84) sequence arereplaced with “LCTPSR,” (SEQ ID NO:17) such that the sulfatase motif hasthe sequence LCTPSR (SEQ ID NO:17). As another example, where themodification is in a CH2/CH3 domain, the surface-accessible loop regioncan have the amino acid sequence KAKGQPR (SEQ ID NO:206), and thealdehyde-tagged sequence can be, e.g., KAKGLCTPSR (SEQ ID NO:207), e.g.,where the “GQP” residues of the KAKGQPR (SEQ ID NO:206) sequence arereplaced with “LCTPS,” (SEQ ID NO:208) such that the sulfatase motif hasthe sequence LCTPSR (SEQ ID NO:17).

As noted above, an isolated aldehyde-tagged Ig polypeptide can comprisea light chain constant region modified to include a sulfatase motif asdescribed above, where the sulfatase motif is in or adjacent asurface-accessible loop region of the Ig polypeptide light chainconstant region. Illustrative examples of surface-accessible loopregions of a light chain constant region are presented in FIGS. 1A and1C.

In some instances, a target immunoglobulin is modified to include asulfatase motif as described above, where the sulfatase motif is within,or adjacent to, a region of an Ig light chain constant regioncorresponding to one or more of: 1) amino acids 130-135; 2) amino acids141-143; 3) amino acid 150; 4) amino acids 162-166; 5) amino acids163-166; 6) amino acids 173-180; 7) amino acids 186-194; 8) amino acids211-212; 9) amino acids 220-225; 10) amino acids 233-236; wherein theamino acid numbering is based on the amino acid numbering of human kappalight chain as depicted in FIG. 1C.

Exemplary surface-accessible loop regions of an Ig light chain (e.g., ahuman kappa light chain) include: 1) RTVAAP (SEQ ID NO:209); 2) PPS; 3)Gly (see, e.g., Gly at position 150 of the human kappa light chainsequence depicted in FIG. 1C); 4) YPREA (SEQ ID NO:210); 5) PREA (SEQ IDNO:226); 6) DNALQSGN (SEQ ID NO:211); 7) TEQDSKDST (SEQ ID NO:212); 8)HK; 9) HQGLSS (SEQ ID NO:213); and 10) RGEC (SEQ ID NO:214), as shown inFIGS. 1A and 1C.

Exemplary surface-accessible loop regions of an Ig lambda light chaininclude QPKAAP (SEQ ID NO:215), PPS, NK, DFYPGAV (SEQ ID NO:216),DSSPVKAG (SEQ ID NO:217), TTP, SN, HKS, EG, and APTECS (SEQ ID NO:218),as shown in FIG. 1C.

In some instances, a target immunoglobulin is modified to include asulfatase motif as described above, where the sulfatase motif is within,or adjacent to, a region of a rat Ig light chain constant regioncorresponding to one or more of: 1) amino acids 1-6; 2) amino acids12-14; 3) amino acids 121-22; 4) amino acids 31-37; 5) amino acids44-51; 6) amino acids 55-57; 7) amino acids 61-62; 8) amino acids 81-83;9) amino acids 91-92; 10) amino acids 102-105; wherein the amino acidnumbering is based on the amino acid numbering of rat light chain as setforth in SEQ ID NO:10 (and depicted in FIG. 1C).

Non-limiting examples of amino acid sequences of aldehyde-tagged IgG1heavy chain polypeptides are shown in FIGS. 7B, 8B, 9B, 11B, 12B, 14,B,15B, 17B, 23B, 25B, 27B, and 29B, with the LCTPSR (SEQ ID NO:17)sulfatase motif in the CH1 domain (see, e.g., FIGS. 7B, 8B, 9B, and23B), CH2 domain (FIGS. 11B, 12B, 14B, and 25B), CH2/CH3 domain (FIGS.15B, and 27B), and near the C-terminus (FIGS. 17B, and 29B).

Non-limiting examples of amino acid sequences of aldehyde-tagged kappalight chain polypeptides are shown in FIGS. 20B and 32B.

A sulfatase motif can be provided within or adjacent one or more ofthese amino acid sequences of such modification sites of an Ig lightchain. For example, an Ig light chain polypeptide can be modified at oneor more of these amino acid sequences to provide a sulfatase motifadjacent and N-terminal and/or adjacent and C-terminal thesemodification sites. Alternatively or in addition, an Ig light chainpolypeptide can be modified at one or more of these amino acid sequencesto provide a sulfatase motif insertion between any two residues of theIg light chain modifications sites. Alternatively or in addition, wherea native amino acid sequence provides for one or more amino acidresidues of a sulfatase motif sequence, selected amino acid residues ofthe modification sites of an Ig light chain polypeptide amino acidsequence can be modified so as to provide a sulfatase motif at themodification site.

The amino acid sequence of a surface-accessible loop region is modifiedto provide a sulfatase motif, where the modifications can includesubstitution and/or insertion. For example, where the modification is ina CL region, the surface-accessible loop region can have the amino acidsequence DNALQSGN (SEQ ID NO:211), and the aldehyde-tagged sequence canbe, e.g., DNALCTPSRQSGN (SEQ ID NO:219), e.g., where the sequence“CTPSR” (SEQ ID NO:204) is inserted between the “DNAL” (SEQ ID NO:220)and the “QSGN” (SEQ ID NO:221) sequences of the surface-accessible loopregion, such that the sulfatase motif is LCTPSR (SEQ ID NO:17).

In one embodiment, modification of an Ig constant region does notsubstantially alter functionality of the heavy chain constant region.For example, the Fc portion (e.g., CH2 and CH3 domains of IgA or IgGantibodies; and CH2, CH3, and CH4 domains of IgM or IgE antibodies) canhave various binding and effector functions. Non limiting examples, ofFc binding and effector functions include, e.g., Fc receptor (FcR)binding, C1q binding, and antibody-dependent cell-mediated cytotoxicity(ADCC) activity. Modification of an Ig constant region to provide analdehyde tag, as described herein, does not substantially increase ordecrease one or more of Fc binding, and any effector function of theheavy chain, e.g., the modification does not increase or decrease theFcR binding and/or an effector function by more than about 1%, about 2%,about 5%, or about 10%, compared to a parent Ig polypeptide.

Modification of an Ig constant region to provide an aldehyde tag, asdescribed herein, does not substantially reduce antigen binding affinityof an antibody comprising the aldehyde-tagged Ig constant region.

Modification of an Ig constant region to provide an aldehyde tag, asdescribed herein, does not substantially reduce production of the Igpolypeptide, e.g., the aldehyde-tagged Ig polypeptide can be expressedin a host cell and can be folded properly so as to result in afunctional polypeptide.

An aldehyde-tagged Ig heavy chain can include an Ig variable region, orcan lack an Ig variable region. Similarly, an aldehyde-tagged Ig lightchain can include an Ig variable region, or can lack an Ig variableregion. Ig variable regions are well known in the art, and can provideantigen-binding specificity to an Ig polypeptide.

An aldehyde-tagged Ig heavy chain can include, in addition to analdehyde tag, one or more additional modifications, e.g., glycosylation,and the like.

The present disclosure provides an aldehyde-tagged antibody comprisingan Ig heavy chain and an Ig light chain, where the Ig heavy chain and/orthe Ig light chain comprises an aldehyde tag. An aldehyde-taggedantibody can include an Ig heavy chain with one, two, three, or morealdehyde tags; and an Ig light chain with no aldehyde tags. Analdehyde-tagged antibody can include an Ig heavy chain with no aldehydetags; and an Ig light chain with one, two, three, or more aldehyde tags.An aldehyde-tagged antibody can include an Ig heavy chain with one, two,three, or more aldehyde tags; and an Ig light chain with one, two,three, or more aldehyde tags.

An aldehyde-tagged antibody of the present disclosure can have any of avariety of antigen-binding specificities. An aldehyde-tagged antibodycan bind any of a variety of antigens, including, e.g., an antigenpresent on a cancer cell; an antigen present on an autoimmune cell; anantigen present on a pathogenic microorganism; an antigen present on avirus-infected cell (e.g., a human immunodeficiency virus-infectedcell), e.g., CD4 or gp120; an antigen present on a diseased cell; andthe like. For example, an aldehyde-tagged antibody can bind an antigen,as noted above, where the antigen is present on the surface of the cell.

For example, an aldehyde-tagged antibody can specifically bind anantigen present on a cancer cell. Non-limiting examples of cancerantigens that can be recognized and bound (e.g., specifically bound) byan aldhehyde-tagged antibody of the present disclosure include antigenspresent on carcinomas, prostate cancer cells, breast cancer cells,colorectal cancer cells, melanoma cells, T-cell leukemia cells, T-celllymphoma cells, B-cell lymphoma cells, non-Hodgkin's lymphoma cells, andthe like.

Non-limiting examples of antigens present on particular cancer cellsinclude, e.g., CA125, CA15-3, CA19-9, L6, Lewis Y, Lewis X, alphafetoprotein, CA 242, placental alkaline phosphatase, prostate specificantigen, prostatic acid phosphatase, epidermal growth factor, MAGE-1,MAGE-2, MAGE-3, MAGE-4, anti-transferrin receptor, p97, MUC1-KLH, HER2,CEA, gp100, MART1, prostate-specific antigen, human chorionicgonadotropin, IL-2 receptor, EphB2, CD19, CD20, CD22, CD52, CD33, CD38,CD40, mucin, P21, MPG, and Neu oncogene product. In some embodiments,the antigen is CD19. In other embodiments, the antigen is CD22.

Non-limiting examples of antibodies that can be modified to include analdehyde tag, as described herein, include, but are not limited to, ananti-CD19 antibody, and an anti-CD22 antibody.

Formylglycine Generating Enzymes (FGEs)

The enzyme that oxidizes cysteine or serine in a sulfatase motif to FGlyis referred to herein as a formylglycine generating enzyme (FGE). Asdiscussed above, “FGE” is used herein to refer to FGly-generatingenzymes that mediate conversion of a cysteine (C) of a sulfatase motifto FGly as well as FGly-generating enzymes that mediate conversion ofserine (S) of a sulfatase motif to FGly. It should be noted that ingeneral, the literature refers to FGly-generating enzymes that convert aC to FGly in a sulfatase motif as FGEs, and refers to enzymes thatconvert S to FGly in a sulfatase motif as Ats-B-like. However, forpurposes of the present disclosure “FGE” is used generically to refer toboth types of FGly-generating enzymes, with the understanding that anappropriate FGE will be selected according to the target reactivepartner containing the appropriate sulfatase motif (i.e., C-containingor S-containing).

As evidenced by the ubiquitous presence of sulfatases having an FGly atthe active site, FGEs are found in a wide variety of cell types,including both eukaryotes and prokaryotes. There are at least two formsof FGEs. Eukaryotic sulfatases contain a cysteine in their sulfatasemotif and are modified by the “SUMF1-type” FGE (Cosma et al. Cell 2003,113, (4), 445-56; Dierks et al. Cell 2003, 113, (4), 435-44). TheFGly-generating enzyme (FGE) is encoded by the SUMF1 gene. Prokaryoticsulfatases can contain either a cysteine or a serine in their sulfatasemotif and are modified either by the “SUMF1-type” FGE or the “AtsB-type”FGE, respectively (Szameit et al. J Biol Chem 1999, 274, (22),15375-81). In eukaryotes, it is believed that this modification happensco-translationally or shortly after translation in the endoplasmicreticulum (ER) (Dierks et al. Proc Natl Acad Sci USA 1997,94(22):11963-8). Without being held to theory, in prokaryotes it isthought that SUMF1-type FGE functions in the cytosol and AtsB-type FGEfunctions near or at the cell membrane. A SUMF2 FGE has also beendescribed in deuterostomia, including vertebrates and echinodermata(see, e.g., Pepe et al. (2003) Cell 113, 445-456, Dierks et al. (2003)Cell 113, 435-444; Cosma et al. (2004) Hum. Mutat. 23, 576-581).

In general, the FGE used to facilitate conversion of cysteine or serineto FGly in a sulfatase motif of an aldehyde tag of a target polypeptideis selected according to the sulfatase motif present in the aldehydetag. The FGE can be native to the host cell in which the aldehyde taggedpolypeptide is expressed, or the host cell can be genetically modifiedto express an appropriate FGE. In some embodiments it may be desired touse a sulfatase motif compatible with a human FGE (e.g., the SUMF1-typeFGE, see, e.g., Cosma et al. Cell 113, 445-56 (2003); Dierks et al. Cell113, 435-44 (2003)), and express the aldehyde tagged protein in a humancell that expresses the FGE or in a host cell, usually a mammalian cell,genetically modified to express a human FGE.

In general, an FGE for use in the methods disclosed herein can beobtained from naturally occurring sources or synthetically produced. Forexample, an appropriate FGE can be derived from biological sources whichnaturally produce an FGE or which are genetically modified to express arecombinant gene encoding an FGE. Nucleic acids encoding a number ofFGEs are known in the art and readily available (see, e.g., Preusser etal. 2005 J. Biol. Chem. 280(15):14900-10 (Epub 2005 Jan. 18); Fang etal. 2004 J Biol Chem. 79(15):14570-8 (Epub 2004 Jan. 28); Landgrebe etal. Gene. 2003 Oct. 16; 316:47-56; Dierks et al. 1998 FEBS Lett.423(1):61-5; Dierks et al. Cell. 2003 May 16; 113(4):435-44; Cosma etal. (2003 May 16) Cell 113(4):445-56; Baenziger (2003 May 16) Cell113(4):421-2 (review); Dierks et al. Cell. 2005 May 20; 121(4):541-52;Roeser et al. (2006 Jan. 3)Proc Natl Acad Sci USA 103(1):81-6; Sardielloet al. (2005 Nov. 1) Hum Mol Genet. 14(21):3203-17; WO 2004/072275; WO2008/036350; U.S. Patent Publication No. 2008/0187956; and GenBankAccession No. NM_182760. Accordingly, the disclosure here provides forrecombinant host cells genetically modified to express an FGE that iscompatible for use with an aldehyde tag of a tagged target polypeptide.In certain embodiments, the FGE used may be a naturally occurring enzyme(may have a wild type amino acid sequence). In other embodiments, theFGE used may be non-naturally occurring, in which case it may, incertain cases, have an amino acid sequence that is at least 80%identical, at least 90% identical or at least 95% identical to that of awild type enzyme. Because FGEs have been studied structurally andfunctionally and the amino acid sequences of several examples of suchenzymes are available, variants that retain enzymatic activity should bereadily designable.

Where a cell-free method is used to convert a sulfatase motif-containingpolypeptide, an isolated FGE can be used. Any convenient proteinpurification procedures may be used to isolate an FGE, see, e.g., Guideto Protein Purification, (Deuthser ed.) (Academic Press, 1990). Forexample, a lysate may be prepared from a cell that produces a desiredFGE, and purified using HPLC, exclusion chromatography, gelelectrophoresis, affinity chromatography, and the like.

Expression Vectors and Genetically Modified Host Cells

The present disclosure provides nucleic acid encoding ald-tagged Igpolypeptides, as well as constructs and host cells containing nucleicacid. Such nucleic acids comprise a sequence of DNA having an openreading frame that encodes an aldehyde tagged Ig polypeptide and, inmost embodiments, is capable, under appropriate conditions, of beingexpressed. “Nucleic acid” encompasses DNA, cDNA, mRNA, and vectorscomprising such nucleic acids.

The present disclosure provides a recombinant nucleic acid comprising anucleotide sequence encoding an aldehyde-tagged Ig polypeptide, asdescribed above. The recombinant nucleic acid can include:

1) a nucleotide sequence encoding an aldehyde-tagged Ig heavy chainconstant region (and not an Ig heavy chain variable region, i.e., wherethe recombinant nucleic acid lacks a nucleotide sequence encoding an IgVH domain);

2) a nucleotide sequence encoding an aldehyde-tagged Ig polypeptide,where the Ig polypeptide comprises an Ig VH domain and analdehyde-tagged Ig heavy chain constant region;

3) a nucleotide sequence encoding an aldehyde-tagged Ig light chainconstant region (and not an Ig light chain variable region, i.e., wherethe recombinant nucleic acid lacks a nucleotide sequence encoding an IgVL domain);

4) a nucleotide sequence encoding an aldehyde-tagged Ig polypeptide,where the Ig polypeptide comprises an Ig VL domain and analdehyde-tagged Ig light chain constant region;

5) a nucleotide sequence encoding an aldehyde-tagged Ig heavy chainconstant region (and not an Ig heavy chain variable region, i.e., wherethe recombinant nucleic acid lacks a nucleotide sequence encoding an IgVH domain); and a nucleotide sequence encoding an aldehyde-tagged Iglight chain constant region (and not an Ig light chain variable region,i.e., where the recombinant nucleic acid lacks a nucleotide sequenceencoding an Ig VL domain);

6) a nucleotide sequence encoding an aldehyde-tagged Ig heavy chainconstant region (and not an Ig heavy chain variable region, i.e., wherethe recombinant nucleic acid lacks a nucleotide sequence encoding an IgVH domain); and a nucleotide sequence encoding an Ig light chainconstant region (and not an Ig light chain variable region, i.e., wherethe recombinant nucleic acid lacks a nucleotide sequence encoding an IgVL domain), where the Ig light chain constant region is not aldehydetagged;

7) a nucleotide sequence encoding an Ig heavy chain constant region (andnot an Ig heavy chain variable region, i.e., where the recombinantnucleic acid lacks a nucleotide sequence encoding an Ig VH domain),where the Ig heavy chain constant region is not aldehyde tagged; and anucleotide sequence encoding an aldehyde-tagged Ig light chain constantregion (and not an Ig light chain variable region, i.e., where therecombinant nucleic acid lacks a nucleotide sequence encoding an Ig VLdomain);

8) a nucleotide sequence encoding a first aldehyde-tagged Igpolypeptide, where the first aldehyde-tagged Ig polypeptide comprises anIg VH domain and an aldehyde-tagged Ig heavy chain constant region; anda nucleotide sequence encoding a second aldehyde-tagged Ig polypeptide,where the second aldehyde-tagged Ig polypeptide comprises an Ig VLdomain and an aldehyde-tagged Ig light chain constant region;

9) a nucleotide sequence encoding a first Ig polypeptide, where thefirst Ig polypeptide is aldehyde tagged, where the first Ig polypeptidecomprises an Ig VH domain and an aldehyde-tagged Ig heavy chain constantregion; and a nucleotide sequence encoding a second Ig polypeptide,where the second Ig polypeptide comprises an Ig VL domain and an Iglight chain constant region, where the Ig light chain constant region isnot aldehyde tagged; or

10) a nucleotide sequence encoding a first Ig polypeptide, where thefirst Ig polypeptide comprises an Ig VH domain and an Ig heavy chainconstant region, where the Ig heavy chain constant region is notaldehyde tagged; and a nucleotide sequence encoding a second Igpolypeptide, where the second Ig polypeptide is aldehyde tagged, wherethe second Ig polypeptide comprising an Ig VL domain and analdehyde-tagged Ig light chain constant region.

The present disclosure provides a recombinant expression vectorcomprising a nucleic acid as described above, where the nucleotidesequence encoding the Ig polypeptide(s) is operably linked to apromoter. In some embodiments, where a subject recombinant expressionvector encodes both Ig heavy and light chains (with or without Igvariable regions), the heavy and light chain-encoding sequences can beoperably linked to the same promoter, or to separate promoters.

Where a recombinant expression vector includes a nucleotide sequenceencoding a heavy chain variable (V_(H)) region and/or a light chainvariable (V_(L)) region, it will be appreciated that a large number ofV_(H) and V_(L) amino acid sequences, and nucleotide sequences encodingsame, are known in the art, and can be used. See, e.g., Kabat et al.,Sequences of Proteins of Immunological Interest, 5th Ed. Public HealthService, National Institutes of Health, Bethesda, Md. (1991).

In those instances in which a recombinant expression vector comprises anucleotide sequence encoding an Ig heavy or Ig light chain withoutvariable region sequences, the vector can include an insertion site foran Ig variable region 5′ of the Ig polypeptide-encoding nucleotidesequence. For example, a recombinant expression vector can comprise, inorder from 5′ to 3′:

1) an insertion site for a nucleotide sequence encoding a VH domain; anda nucleotide sequence encoding an aldehyde-tagged Ig heavy chainconstant region;

2) an insertion site for a nucleotide sequence encoding a VL domain; anda nucleotide sequence encoding an aldehyde-tagged Ig light chainconstant region.

The present disclosure also provides a library of recombinant expressionvectors, where the library can include a plurality of member recombinantexpression vectors, e.g.:

1) a first recombinant expression vector comprising, in order from 5′ to3′, an insertion site for a nucleotide sequence encoding a VH domain;and a nucleotide sequence encoding a first aldehyde-tagged Ig heavychain constant region comprising an aldehyde tag in or adjacent a firstsurface-accessible loop region;

2) a second recombinant expression vector comprising, in order from 5′to 3′, an insertion site for a nucleotide sequence encoding a VH domain;and a nucleotide sequence encoding a second aldehyde-tagged Ig heavychain constant region comprising an aldehyde tag in or adjacent a secondsurface-accessible loop region;

3) a third recombinant expression vector comprising, in order from 5′ to3′, an insertion site for a nucleotide sequence encoding a VH domain;and a nucleotide sequence encoding a third aldehyde-tagged Ig heavychain constant region comprising an aldehyde tag in or adjacent a thirdsurface-accessible loop region;

and combinations thereof, where each additional member recombinantexpression vectors can include nucleotide sequences encodingaldehyde-tagged Ig polypeptides having aldehyde tags in or adjacent adifferent surface-accessible loop region.

In some instances, a recombinant expression vector in the library willalso include a nucleotide sequence encoding an Ig light chain, which mayor may not include a variable region, and which may or may not bealdehyde tagged.

The present disclosure also provides a library of recombinant expressionvectors, where the library can include a plurality of member recombinantexpression vectors, e.g.:

1) a first recombinant expression vector comprising, in order from 5′ to3′, an insertion site for a nucleotide sequence encoding a VL domain;and a nucleotide sequence encoding a first aldehyde-tagged Ig lightchain constant region comprising an aldehyde tag in or adjacent a firstsurface-accessible loop region;

2) a second recombinant expression vector comprising, in order from 5′to 3′, an insertion site for a nucleotide sequence encoding a VL domain;and a nucleotide sequence encoding a second aldehyde-tagged Ig lightchain constant region comprising an aldehyde tag in or adjacent a secondsurface-accessible loop region;

3) a third recombinant expression vector comprising, in order from 5′ to3′, an insertion site for a nucleotide sequence encoding a VL domain;and a nucleotide sequence encoding a third aldehyde-tagged Ig lightchain constant region comprising an aldehyde tag in or adjacent a thirdsurface-accessible loop region;

and combinations thereof, where each additional member recombinantexpression vectors can include nucleotide sequences encodingaldehyde-tagged Ig polypeptides having aldehyde tags in or adjacent adifferent surface-accessible loop region.

In some instances, a recombinant expression vector in the library willalso include a nucleotide sequence encoding an Ig heavy chain, which mayor may not include a variable region, and which may or may not bealdehyde tagged.

FIG. 2 depicts an example of a scheme for generating a library ofaldehyde-tagged Ig polypeptides, in which each member Ig polypeptidecomprises an aldehyde tag at a different location from the othermembers. For example, an Ig heavy chain or an Ig light chain, a “taggedcassette” is modified with aldehyde tags that can be further elaboratedchemically. These cassettes can be applied to different Fvs forantibody-drug conjugate production.

Nucleic acids contemplated herein can be provided as part of a vector(also referred to as a construct), a wide variety of which are known inthe art and need not be elaborated upon herein. Exemplary vectorsinclude, but are not limited to, plasmids; cosmids; viral vectors (e.g.,retroviral vectors); non-viral vectors; artificial chromosomes (yeastartificial chromosomes (YAC's), BAC's, etc.); mini-chromosomes; and thelike. The choice of vector will depend upon a variety of factors such asthe type of cell in which propagation is desired and the purpose ofpropagation.

Vectors can provide for extrachromosomal maintenance in a host cell orcan provide for integration into the host cell genome. Vectors are amplydescribed in numerous publications well known to those in the art,including, e.g., Short Protocols in Molecular Biology, (1999) F.Ausubel, et al., eds., Wiley & Sons. Vectors may provide for expressionof the nucleic acids encoding a polypeptide of interest (e.g., analdehyde tagged polypeptide, an FGE, etc.), may provide for propagatingthe subject nucleic acids, or both.

Exemplary vectors that may be used include but are not limited to thosederived from recombinant bacteriophage DNA, plasmid DNA or cosmid DNA.For example, plasmid vectors such as pBR322, pUC 19/18, pUC 118, 119 andthe M13 mp series of vectors may be used. Bacteriophage vectors mayinclude λgt10, λgt11, λgt18-23, λZAP/R and the EMBL series ofbacteriophage vectors. Cosmid vectors that may be utilized include, butare not limited to, pJB8, pCV 103, pCV 107, pCV 108, pTM, pMCS, pNNL,pHSG274, COS202, COS203, pWE15, pWE16 and the charomid 9 series ofvectors. Alternatively, recombinant virus vectors may be engineered,including but not limited to those derived from viruses such as herpesvirus, retroviruses, vaccinia virus, poxviruses, adenoviruses,adeno-associated viruses, or bovine papilloma virus.

For expression of a protein of interest (e.g., an aldehyde-tagged Igpolypeptide or an FGE), an expression cassette may be employed. Thus,the present invention provides a recombinant expression vectorcomprising a subject nucleic acid. The expression vector provides atranscriptional and translational regulatory sequence, and may providefor inducible or constitutive expression, where the coding region isoperably linked under the transcriptional control of the transcriptionalinitiation region, and a transcriptional and translational terminationregion. These control regions may be native to the gene encoding thepolypeptide (e.g., the Ig polypeptide or the FGE), or may be derivedfrom exogenous sources. In general, the transcriptional andtranslational regulatory sequences may include, but are not limited to,promoter sequences, ribosomal binding sites, transcriptional start andstop sequences, translational start and stop sequences, and enhancer oractivator sequences. In addition to constitutive and induciblepromoters, strong promoters (e.g., T7, CMV, and the like) find use inthe constructs described herein, particularly where high expressionlevels are desired in an in vivo (cell-based) or in an in vitroexpression system. Further exemplary promoters include mouse mammarytumor virus (MMTV) promoters, Rous sarcoma virus (RSV) promoters,adenovirus promoters, the promoter from the immediate early gene ofhuman CMV (Boshart et al., Cell 41:521-530, 1985), and the promoter fromthe long terminal repeat (LTR) of RSV (Gorman et al., Proc. Natl. Acad.Sci. USA 79:6777-6781, 1982). The promoter can also be provided by, forexample, a 5′UTR of a retrovirus.

Expression vectors generally have convenient restriction sites locatednear the promoter sequence to provide for the insertion of nucleic acidsequences encoding proteins of interest. A selectable marker operativein the expression host may be present to facilitate selection of cellscontaining the vector. In addition, the expression construct may includeadditional elements. For example, the expression vector may have one ortwo replication systems, thus allowing it to be maintained in organisms,for example in mammalian or insect cells for expression and in aprokaryotic host for cloning and amplification. In addition theexpression construct may contain a selectable marker gene to allow theselection of transformed host cells. Selection genes are well known inthe art and will vary with the host cell used.

Expression constructs encoding aldehyde tagged Ig polypeptides can alsobe generated using amplification methods (e.g., a polymerase chainreaction (PCR)), where at least one amplification primer (i.e., at leastone of a forward or reverse primer) includes a nucleic acid sequenceencoding an aldehyde tag. For example, an amplification primer having analdehyde tag-encoding sequence is designed to provide for amplificationof a nucleic acid encoding an Ig polypeptide. The extension product thatresults from polymerase-mediated synthesis from the aldehydetag-containing forward primer produces a nucleic acid amplificationproduct encoding a fusion protein composed of an aldehyde-tagged Igpolypeptide. The amplification product is then inserted into anexpression construct of choice to provide an aldehyde tagged polypeptideexpression construct.

Host Cells

The present disclosure provides genetically modified host cellscomprising a subject nucleic acid, including a genetically modified hostcell comprising a recombinant expression vector as described above. Anyof a number of suitable host cells can be used in the production of analdehyde-tagged Ig polypeptide. The host cell used for production of analdehyde tagged Ig polypeptide can optionally provide for FGE-mediatedconversion, so that the Ig polypeptide produced contains anFGly-containing aldehyde tag following expression and modification byFGE. Alternatively the host cell can provide for production of anunconverted aldehyde tagged Ig polypeptide (e.g., due to lack ofexpression of an FGE that facilitates conversion of the aldehyde tag).

The aldehyde moiety of a converted aldehyde tag can be used for avariety of applications including, but not limited to, visualizationusing fluorescence or epitope labeling (e.g., electron microscopy usinggold particles equipped with aldehyde reactive groups); proteinimmobilization (e.g., protein microarray production); protein dynamicsand localization studies and applications; and conjugation of proteinswith a moiety of interest (e.g., moieties that improve a parentprotein's half-life (e.g., poly(ethylene glycol)), targeting moieties(e.g., to enhance delivery to a site of action), and biologically activemoieties (e.g., a therapeutic moiety).

In general, the polypeptides described herein may be expressed inprokaryotes or eukaryotes in accordance with conventional ways,depending upon the purpose for expression. Thus, the present inventionfurther provides a host cell, e.g., a genetically modified host cellthat comprises a nucleic acid encoding an aldehyde tagged polypeptide.The host cell can further optionally comprise a recombinant FGE, whichmay be endogenous or heterologous to the host cell.

Host cells for production (including large scale production) of anunconverted or (where the host cell expresses a suitable FGE) convertedaldehyde tagged Ig polypeptide, or for production of an FGE (e.g., foruse in a cell-free method) can be selected from any of a variety ofavailable host cells. Exemplary host cells include those of aprokaryotic or eukaryotic unicellular organism, such as bacteria (e.g.,Escherichia coli strains, Bacillus spp. (e.g., B. subtilis), and thelike) yeast or fungi (e.g., S. cerevisiae, Pichia spp., and the like),and other such host cells can be used. Exemplary host cells originallyderived from a higher organism such as insects, vertebrates,particularly mammals, (e.g. CHO, HEK, and the like), may be used as theexpression host cells.

Suitable mammalian cell lines include, but are not limited to, HeLacells (e.g., American Type Culture Collection (ATCC) No. CCL-2), CHOcells (e.g., ATCC Nos. CRL9618 and CRL9096), CHO DG44 cells (Urlaub(1983) Cell 33:405), CHO-K1 cells (ATCC CCL-61), 293 cells (e.g., ATCCNo. CRL-1573), Vero cells, NIH 3T3 cells (e.g., ATCC No. CRL-1658),Huh-7 cells, BHK cells (e.g., ATCC No. CCL10), PC12 cells (ATCC No.CRL1721), COS cells, COS-7 cells (ATCC No. CRL1651), RAT1 cells, mouse Lcells (ATCC No. CCLI.3), human embryonic kidney (HEK) cells (ATCC No.CRL1573), HLHepG2 cells, and the like.

Specific expression systems of interest include bacterial, yeast, insectcell and mammalian cell derived expression systems. Representativesystems from each of these categories are provided below.

The product can be recovered by any appropriate means known in the art.Further, any convenient protein purification procedures may be employed,where suitable protein purification methodologies are described in Guideto Protein Purification, (Deuthser ed.) (Academic Press, 1990). Forexample, a lysate may prepared from a cell comprising the expressionvector expressing the ald-tagged Ig polypeptide, and purified using highperformance liquid chromatography (HPLC), exclusion chromatography, gelelectrophoresis, affinity chromatography, and the like.

Methods for Conversion and Modification of an Aldehyde Tag

Conversion of an aldehyde tag present in an aldehyde tagged Igpolypeptide can be accomplished by cell-based (in vivo) or cell-freemethods (in vitro). Similarly, modification of a converted aldehyde tagof an aldehyde tagged polypeptide can be accomplished by cell-based (invivo) or cell-free methods (in vitro). These are described in moredetail below.

“In Vivo” Host Cells Conversion and Modification

Conversion of an aldehyde tag of an aldehyde tagged polypeptide can beaccomplished by expression of the aldehyde tagged polypeptide in a cellthat contains a suitable FGE. In this embodiment, conversion of thecysteine or serine of the aldehyde tag occurs during or followingtranslation in the host cell. The FGE of the host cell can be endogenousto the host cell, or the host cell can be recombinant for a suitable FGEthat is heterologous to the host cell. FGE expression can be provided byan expression system endogenous to the FGE gene (e.g., expression isprovided by a promoter and other control elements present in the nativeFGE gene of the host cell), or can be provided by from a recombinantexpression system in which the FGE coding sequence is operably linked toa heterologous promoter to provide for constitutive or inducibleexpression.

Conditions suitable for use to accomplish conjugation of a reactivepartner moiety to an aldehyde tagged polypeptide are similar to thosedescribed in Mahal et al. (1997 May 16) Science 276(5315):1125-8.

In some instances, where a method is carried out in a cell, the cell isin vitro, e.g., in in vitro cell culture, e.g., where the cell iscultured in vitro in a single-cell suspension or as an adherent cell.

“In Vitro” (Cell-Free) Conversion and Modification

In vitro (cell-free) conversion of an aldehyde tag of an aldehyde taggedIg polypeptide can be accomplished by contacting an aldehyde taggedpolypeptide with an FGE under conditions suitable for conversion of acysteine or serine of a sulfatase motif of the aldehyde tag to an FGly.For example, nucleic acid encoding an aldehyde tagged Ig polypeptide canbe expressed in an in vitro transcription/translation system in thepresence of a suitable FGE to provide for production of convertedaldehyde tagged Ig polypeptides.

Alternatively, isolated, unconverted aldehyde tagged Ig polypeptide canbe isolated following recombinant production in a host cell lacking asuitable FGE or by synthetic production. The isolated aldehyde tagged Igpolypeptide is then contacted with a suitable FGE under conditions toprovide for aldehyde tag conversion. The aldehyde tagged Ig polypeptidecan be unfolded by methods known in the art (e.g., using heat,adjustment of pH, chaotropic agents, (e.g., urea, and the like), organicsolvents (e.g., hydrocarbons: octane, benzene, chloroform), etc.) andthe denatured protein contacted with a suitable FGE. The ald-tagged Igpolypeptide can then be refolded under suitable conditions.

With respect to modification of converted aldehyde tagged, modificationis normally carried out in vitro. A converted aldehyde tagged Igpolypeptide is isolated from a production source (e.g., recombinant hostcell production, synthetic production), and contacted with a reactivepartner-containing drug or other moiety under conditions suitable toprovide for conjugation of the drug or other moiety to the FGly of thealdehyde tag.

In some instances, a combination of cell-based conversion and cell-freeconversion is carried out, to generate a converted aldehyde tag;followed by cell-free modification of the converted aldehyde tag. Insome embodiments, a combination of cell-free conversion and cell-basedconversion is carried out.

Moieties for Modification of Immunoglobulin Polypeptides

The aldehyde tagged, FGly-containing Ig polypeptides can be subjected tomodification to provide for attachment of a wide variety of moieties.Exemplary molecules of interest include, but are not necessarily limitedto, a drug, a detectable label, a small molecule, a water-solublepolymer, a synthetic peptide, and the like.

Thus, the present disclosure provides an Ig polypeptide conjugate (alsoreferred to herein as an “Ig conjugate”), the Ig conjugate comprising:

an Ig polypeptide (e.g., an Ig heavy chain or an Ig light chain, or anIg comprising both heavy and light chains) and a covalently conjugatedmoiety, wherein the Ig polypeptide comprises a modified sulfatase motifof the formula:X₁(FGly′)X₂Z₂X₃Z₃  (SEQ ID NO: 303)

where FGly′ is of the formula:

wherein J¹ is the covalently bound moiety;

each L¹ is a divalent moiety independently selected from alkylene,substituted alkylene, alkenylene, substituted alkenylene, alkynylene,alkynylene, arylene, substituted arylene, cycloalkylene, substitutedcycloalkylene, heteroarylene, substituted heteroarylene, heterocyclene,substituted heterocyclene, acyl, amido, acyloxy, urethanylene,thioester, sulfonyl, sulfonamide, sulfonyl ester, —O—, —S—, —NH—, andsubstituted amine;

n is a number selected from zero to 40;

Z₂ is a proline or alanine residue;

X₁ is present or absent and, when present, is any amino acid, with theproviso that when the sulfatase motif is at an N-terminus of thepolypeptide, X₁ is present;

X₂ and X₃ are each independently any amino acid; and

Z₃ is an aliphatic amino acid or basic amino acid;

and

wherein the Ig conjugate presents the covalently bound moiety on asolvent-accessible surface when in a folded state.

The present disclosure provides an antibody conjugated to a moiety ofinterest, where an antibody conjugated to a moiety of interest isreferred to as an “antibody conjugate.” An antibody conjugate of thepresent disclosure can include: 1) Ig heavy chain constant regionconjugated to a moiety of interest; and an Ig light chain constantregion conjugated to a moiety of interest; 2) an Ig heavy chain constantregion conjugated to a moiety of interest; and an Ig light chainconstant region that is not conjugated to a moiety of interest; or 3) anIg heavy chain constant region that is not conjugated to a moiety ofinterest; and an Ig light chain constant region conjugated to a moietyof interest. A subject antibody conjugate can also include VH and/or VLdomains.

The moiety of interest is provided as component of a reactive partnerfor reaction with an aldehyde of the FGly residue of a convertedaldehyde tag of the tagged Ig polypeptide. Since the methods of taggedIg polypeptide modification are compatible with conventional chemicalprocesses, the methods of the present disclosure can exploit a widerange of commercially available reagents to accomplish attachment of amoiety of interest to an FGly residue of an aldehyde tagged Igpolypeptide. For example, aminooxy, hydrazide, or thiosemicarbazidederivatives of a number of moieties of interest are suitable reactivepartners, and are readily available or can be generated using standardchemical methods.

For example, to attach a poly(ethylene glycol) (PEG) moiety to a taggedIg polypeptide, an aminooxy-PEG can be generated from monoamino-PEGs andaminooxyglycine using standard protocols. The aminooxy-PEG can then bereacted with a converted (e.g., FGly-modified) aldehyde tagged Igpolypeptide to provide for attachment of the PEG moiety. Delivery of abiotin moiety to a converted aldehyde tagged polypeptide can beaccomplished using aminooxy biotin, biotin hydrazide or 2,4dinitrophenylhydrazine.

Provided the present disclosure, the ordinarily skilled artisan canreadily adapt any of a variety of moieties to provide a reactive partnerfor conjugation to an aldehyde tagged polypeptide as contemplatedherein. The ordinarily skilled artisan will appreciate that factors suchas pH and steric hindrance (i.e., the accessibility of the aldehyde tagto reaction with a reactive partner of interest) are of importance.Modifying reaction conditions to provide for optimal conjugationconditions is well within the skill of the ordinary artisan, and isroutine in the art. In general, it is normally desirable to conductionconjugation reactions at a pH below 7, with a pH of about 5.5, about 6,about 6.5, usually about 5.5 being optimal. Where conjugation isconducted with an aldehyde tagged polypeptide present in or on a livingcell, the conditions are selected so as to be physiologicallycompatible. For example, the pH can be dropped temporarily for a timesufficient to allow for the reaction to occur but within a periodtolerated by the cell having an aldehyde tag (e.g., from about 30 min to1 hour). Physiological conditions for conducting modification ofaldehyde tagged polypeptides on a cell surface can be similar to thoseused in a ketone-azide reaction in modification of cells bearingcell-surface azides (see, e.g., U.S. Pat. No. 6,570,040).

In general, the moiety or moieties can provide for one or more of a widevariety of functions or features. Exemplary moieties include detectablelabels (e.g., dye labels (e.g., chromophores, fluorophores), biophysicalprobes (spin labels, nuclear magnetic resonance (NMR) probes), FörsterResonance Energy Transfer (FRET)-type labels (e.g., at least one memberof a FRET pair, including at least one member of a fluorophore/quencherpair), Bioluminescence Resonance Energy Transfer (BRET)-type labels(e.g., at least one member of a BRET pair), immunodetectable tags (e.g.,FLAG®, His(6), and the like), localization tags (e.g., to identifyassociation of a tagged polypeptide at the tissue or molecular celllevel (e.g., association with a tissue type, or particular cellmembrane)), and the like); light-activated dynamic moieties (e.g.,azobenzene mediated pore closing, azobenzene mediated structuralchanges, photodecaging recognition motifs); water soluble polymers(e.g., PEGylation); purification tags (e.g., to facilitate isolation byaffinity chromatography (e.g., attachment of a FLAG® epitope, e.g.,DYKDDDDK (SEQ ID NO:222)); membrane localization domains (e.g., lipidsor glycophosphatidylinositol (GPI)-type anchors); immobilization tags(e.g., to facilitate attachment of the polypeptide to a surface,including selective attachment); drugs (e.g., to facilitate drugtargeting, e.g., through attachment of the drug to an antibody);targeted delivery moieties, (e.g., ligands for binding to a targetreceptor (e.g., to facilitate viral attachment, attachment of atargeting protein present on a liposome, etc.)), and the like.

Specific, non-limiting examples are provided below.

Detectable Labels

The compositions and methods of the present disclosure can be used todeliver a detectable label to an aldehyde tagged Ig, e.g., where J¹ is adetectable label. Exemplary detectable labels include, but are notnecessarily limited to, fluorescent molecules (e.g., autofluorescentmolecules, molecules that fluoresce upon contact with a reagent, etc.),radioactive labels (e.g., ¹¹¹In, ¹²⁵I, ¹³¹I, ²¹²B, ⁹⁰Y, ¹⁸⁶Rh, and thelike); biotin (e.g., to be detected through reaction of biotin andavidin); fluorescent tags; imaging reagents, and the like. Detectablelabels also include peptides or polypeptides that can be detected byantibody binding, e.g., by binding of a detectably labeled antibody orby detection of bound antibody through a sandwich-type assay.

Attachment of Target Molecules to a Support

The methods can provide for conjugation of an aldehyde taggedimmunoglobulin to a moiety to facilitate attachment of theimmunoglobulin to a solid substratum (e.g., to facilitate assays), or toa moiety to facilitate easy separation (e.g., a hapten recognized by anantibody bound to a magnetic bead). In one embodiment, the methods ofthe invention are used to provide for attachment of a protein to anarray (e.g., chip) in a defined orientation. For example, a polypeptidehaving an aldehyde tag at a selected site (e.g., at or near theN-terminus) can be generated, and the methods and compositions of theinvention used to deliver a moiety to the converted aldehyde tag. Themoiety can then be used as the attachment site for affixing thepolypeptide to a support (e.g., solid or semi-solid support,particularly a support suitable for use as a microchip inhigh-throughput assays).

Attachment of Molecules for Delivery to a Target Site

The reactive partner for the aldehyde tagged polypeptide can comprise asmall molecule drug, toxin, or other molecule for delivery to the celland which can provide for a pharmacological activity or can serve as atarget for delivery of other molecules.

Also contemplated is use of a reactive partner that comprises one of apair of binding partners (e.g., a ligand, a ligand-binding portion of areceptor, a receptor-binding portion of a ligand, etc.). For example,the reactive partner can comprise a polypeptide that serves as a viralreceptor and, upon binding with a viral envelope protein or viral capsidprotein, facilitates attachment of virus to the cell surface on whichthe modified aldehyde tagged protein is expressed. Alternatively, thereactive partner comprises an antigen that is specifically bound by anantibody (e.g., monoclonal antibody), to facilitate detection and/orseparation of host cells expressing the modified aldehyde taggedpolypeptide.

Water-Soluble Polymers

In some cases, an Ig conjugate comprises a covalently linkedwater-soluble polymer, e.g., where J¹ is a water-soluble polymer. Amoiety of particular interest is a water-soluble polymer. A“water-soluble polymer” refers to a polymer that is soluble in water andis usually substantially non-immunogenic, and usually has an atomicmolecular weight greater than about 1,000 Daltons. The methods andcompositions described herein can be used to attach one or morewater-soluble polymers to an aldehyde tagged polypeptide. Attachment ofa water-soluble polymer (e.g., PEG) of a polypeptide, particularly apharmaceutically active (therapeutic) polypeptide can be desirable assuch modification can increase therapeutic index by increasing serumhalf-life as a result of increased proteolytic stability and/ordecreased renal clearance. Additionally, attachment of one or morepolymers (e.g., PEGylation) can reduce immunogenicity of proteinpharmaceuticals.

In some embodiments, the water-soluble polymer has an effectivehydrodynamic molecular weight of greater than about 10,000 Da, greaterthan about 20,000 to 500,000 Da, greater than about 40,000 Da to 300,000Da, greater than about 50,000 Da to 70,000 Da, usually greater thanabout 60,000 Da. In some embodiments, the water-soluble polymer has aneffective hydrodynamic molecular weight of from about 10 kDa to about 20kDa, from about 20 kDa to about 25 kDa, from about 25 kDa to about 30kDa, from about 30 kDa to about 50 kDa, or from about 50 kDa to about100 kDa. By “effective hydrodynamic molecular weight” is intended theeffective water-solvated size of a polymer chain as determined byaqueous-based size exclusion chromatography (SEC). When thewater-soluble polymer contains polymer chains having polyalkylene oxiderepeat units, such as ethylene oxide repeat units, each chain can havean atomic molecular weight of between about 200 Da and about 80,000 Da,or between about 1,500 Da and about 42,000 Da, with 2,000 to about20,000 Da being of particular interest. Unless referred to specifically,molecular weight is intended to refer to atomic molecular weight.Linear, branched, and terminally charged water soluble polymers (e.g.,PEG) are of particular interest.

Polymers useful as moieties to be attached to an aldehyde taggedpolypeptide can have a wide range of molecular weights, and polymersubunits. These subunits may include a biological polymer, a syntheticpolymer, or a combination thereof. Examples of such water-solublepolymers include: dextran and dextran derivatives, including dextransulfate, P-amino cross linked dextrin, and carboxymethyl dextrin,cellulose and cellulose derivatives, including methylcellulose andcarboxymethyl cellulose, starch and dextrines, and derivatives andhydroylactes of starch, polyalklyene glycol and derivatives thereof,including polyethylene glycol, methoxypolyethylene glycol, polyethyleneglycol homopolymers, polypropylene glycol homopolymers, copolymers ofethylene glycol with propylene glycol, wherein said homopolymers andcopolymers are unsubstituted or substituted at one end with an alkylgroup, heparin and fragments of heparin, polyvinyl alcohol and polyvinylethyl ethers, polyvinylpyrrolidone, aspartamide, and polyoxyethylatedpolyols, with the dextran and dextran derivatives, dextrine and dextrinederivatives. It will be appreciated that various derivatives of thespecifically recited water-soluble polymers are also contemplated.

Water-soluble polymers such as those described above are well known,particularly the polyalkylene oxide based polymers such as polyethyleneglycol “PEG” (See. e.g., “Poly(ethylene glycol) Chemistry: Biotechnicaland Biomedical Applications”, J. M. Harris, Ed., Plenum Press, New York,N.Y. (1992); and “Poly(ethylene glycol) Chemistry and BiologicalApplications”, J. M. Harris and S. Zalipsky, Eds., ACS (1997); andInternational Patent Applications: WO 90/13540, WO 92/00748, WO92/16555, WO 94/04193, WO 94/14758, WO 94/17039, WO 94/18247, WO94/28937, WO 95/11924, WO 96/00080, WO 96/23794, WO 98/07713, WO98/41562, WO 98/48837, WO 99/30727, WO 99/32134, WO 99/33483, WO99/53951, WO 01/26692, WO 95/13312, WO 96/21469, WO 97/03106, WO99/45964, and U.S. Pat. Nos. 4,179,337; 5,075,046; 5,089,261; 5,100,992;5,134,192; 5,166,309; 5,171,264; 5,213,891; 5,219,564; 5,275,838;5,281,698; 5,298,643; 5,312,808; 5,321,095; 5,324,844; 5,349,001;5,352,756; 5,405,877; 5,455,027; 5,446,090; 5,470,829; 5,478,805;5,567,422; 5,605,976; 5,612,460; 5,614,549; 5,618,528; 5,672,662;5,637,749; 5,643,575; 5,650,388; 5,681,567; 5,686,110; 5,730,990;5,739,208; 5,756,593; 5,808,096; 5,824,778; 5,824,784; 5,840,900;5,874,500; 5,880,131; 5,900,461; 5,902,588; 5,919,442; 5,919,455;5,932,462; 5,965,119; 5,965,566; 5,985,263; 5,990,237; 6,011,042;6,013,283; 6,077,939; 6,113,906; 6,127,355; 6,177,087; 6,180,095;6,194,580; 6,214,966).

Exemplary polymers of interest include those containing a polyalkyleneoxide, polyamide alkylene oxide, or derivatives thereof, includingpolyalkylene oxide and polyamide alkylene oxide comprising an ethyleneoxide repeat unit of the formula —(CH2-CH2-O)—. Further exemplarypolymers of interest include a polyamide having a molecular weightgreater than about 1,000 Daltons of the formula —[C(O)—X—C(O)—NH—Y—NH]n-or —[NH—Y—NH—C(O)—X—C(O)]_(n)—, where X and Y are divalent radicals thatmay be the same or different and may be branched or linear, and n is adiscrete integer from 2-100, usually from 2 to 50, and where either orboth of X and Y comprises a biocompatible, substantially non-antigenicwater-soluble repeat unit that may be linear or branched. Furtherexemplary water-soluble repeat units comprise an ethylene oxide of theformula —(CH₂—CH₂—O)— or —(CH₂—CH₂—O)—. The number of such water-solublerepeat units can vary significantly, with the usual number of such unitsbeing from 2 to 500, 2 to 400, 2 to 300, 2 to 200, 2 to 100, and mostusually 2 to 50. An exemplary embodiment is one in which one or both ofX and Y is selected from: —((CH₂)_(n1)—(CH₂—CH₂—O)_(n2)—(CH₂)— or—((CH₂)_(n1)—(O—CH₂—CH₂)_(n2)—(CH₂)_(n-1)—), where n1 is 1 to 6, 1 to 5,1 to 4 and most usually 1 to 3, and where n2 is 2 to 50, 2 to 25, 2 to15, 2 to 10, 2 to 8, and most usually 2 to 5. A further exemplaryembodiment is one in which X is —(CH₂—CH₂)—, and where Y is—(CH₂—(CH₂—CH₂—O)₃—CH₂—CH₂—CH₂)— or —(CH₂—CH₂—CH₂—(O—CH₂—CH₂)₃—CH₂)—.

The polymer can include one or more spacers or linkers. Exemplaryspacers or linkers include linear or branched moieties comprising one ormore repeat units employed in a water-soluble polymer, diamino and ordiacid units, natural or unnatural amino acids or derivatives thereof,as well as aliphatic moieties, including alkyl, aryl, heteroalkyl,heteroaryl, alkoxy, and the like, which can contain, for example, up to18 carbon atoms or even an additional polymer chain.

The polymer moiety, or one or more of the spacers or linkers of thepolymer moiety when present, may include polymer chains or units thatare biostable or biodegradable. For example, Polymers with repeatlinkages have varying degrees of stability under physiologicalconditions depending on bond lability. Polymers with such bonds can becategorized by their relative rates of hydrolysis under physiologicalconditions based on known hydrolysis rates of low molecular weightanalogs, e.g., from less stable to more stable, e.g., polyurethanes(—NH—C(O)—O—)>polyorthoesters (—O—C((OR)(R′))—O—)>polyamides(—C(O)—NH—). Similarly, the linkage systems attaching a water-solublepolymer to a target molecule may be biostable or biodegradable, e.g.,from less stable to more stable: carbonate (—O—C(O)—O—)>ester(—C(O)—O—)>urethane (—NH—C(O)—O—)>orthoester (—O—C((OR)(R′))—O—)>amide(—C(O)—NH—). In general, it may be desirable to avoid use of sulfatedpolysaccharide, depending on the lability of the sulfate group. Inaddition, it may be less desirable to use polycarbonates and polyesters.These bonds are provided by way of example, and are not intended tolimit the types of bonds employable in the polymer chains or linkagesystems of the water-soluble polymers useful in the modified aldehydetagged polypeptides disclosed herein.

Synthetic Peptides

In some cases, an Ig conjugate comprises a covalently linked peptide,e.g., where J¹ is a peptide. Suitable peptides include, but are notlimited to, cytotoxic peptides; angiogenic peptides; anti-angiogenicpeptides; peptides that activate B cells; peptides that activate Tcells; anti-viral peptides; peptides that inhibit viral fusion; peptidesthat increase production of one or more lymphocyte populations;anti-microbial peptides; growth factors; growth hormone-releasingfactors; vasoactive peptides; anti-inflammatory peptides; peptides thatregulate glucose metabolism; an anti-thrombotic peptide; ananti-nociceptive peptide; a vasodilator peptide; a platelet aggregationinhibitor; an analgesic; and the like.

Where J¹ is a peptide, the peptide can be chemically synthesized toinclude a group reactive with a converted FGly-containing Igpolypeptide. A suitable synthetic peptide has a length of from about 5amino acids to about 100 amino acids, or longer than 100 amino acids;e.g., a suitable peptide has a length of from about 5 amino acids (aa)to about 10 aa, from about 10 aa to about 15 aa, from about 15 aa toabout 20 aa, from about 20 aa to about 25 aa, from about 25 aa to about30 aa, from about 30 aa to about 40 aa, from about 40 aa to about 50 aa,from about 50 aa to about 60 aa, from about 60 aa to about 70 aa, fromabout 70 aa to about 80 aa, from about 80 aa to about 90 aa, or fromabout 90 aa to about 100 aa.

A peptide can be modified to contain an α-nucleophile-containing moiety(e.g., an aminooxy or hydrazide moiety), e.g., can be reacted with theFGly-containing Ig polypeptide to yield a conjugate in which thealdehyde-tagged Ig polypeptide and peptide are linked by a hydrazone oroxime bond, respectively. Exemplary methods of synthesizing a peptide,such that the synthetic peptide comprising a reactive group reactivewith a converted aldehyde tag, are described above.

Suitable peptides include, but are not limited to, hLF-11 (an 11-aminoacid N-terminal fragment of lactoferrin), an anti-microbial peptide;granulysin, an anti-microbial peptide; Plectasin (NZ2114; SAR 215500),an anti-microbial peptide; viral fusion inhibitors such as Fuzeon(enfuvirtide), TRI-1249 (T-1249; see, e.g., Matos et al. (2010) PLoS One5:e9830), TRI-2635 (T-2635; see, e.g., Eggink et al. (2009) J. Biol.Chem. 284:26941), T651, and TRI-1144; C5a receptor inhibitors such asPMX-53, JPE-1375, and JSM-7717; POT-4, a human complement factor C3inhibitor; Pancreate (an INGAP derivative sequence, a HIP-human proisletprotein); somatostatin; a somatostatin analog such as DEBIO 8609(Sanvar), octreotide, octreotide (C2L), octreotide QLT, octreotide LAR,Sandostatin LAR, SomaLAR, Somatuline (lanreotide), see, e.g., Deghenghiet al. (2001) Endocrine 14:29; TH9507 (Tesamorelin, a growthhormone-releasing factor); POL7080 (a protegrin analog, ananti-microbial peptide); relaxin; a corticotropin releasing factoragonist such as urotensin, sauvagine, and the like; a heat shock proteinderivative such as DiaPep277; a human immunodeficiency virus entryinhibitor; a heat shock protein-20 mimic such as AZX100; a thrombinreceptor activating peptide such as TP508 (Chrysalin); a urocortin 2mimic (e.g., a CRF2 agonist) such as urocortin-2; an immune activatorsuch as Zadaxin (thymalfasin; thymosin-al), see, e.g., Sjogren (2004) J.Gastroenterol. Hepatol. 19:S69; a hepatitis C virus (HCV) entryinhibitorE2 peptide such as HCV3; an atrial natriuretic peptide such asHANP (Sun 4936; carperitide); an annexin peptide; a defensin(anti-microbial peptide) such as hBD2-4; a defensin (anti-microbialpeptide) such as hBD-3; a defensin (anti-microbial peptide) such asPMX-30063; a histatin (anti-microbial peptide) such as histatin-3,histatin-5, histatin-6, and histatin-9; a histatin (anti-microbialpeptide) such as PAC-113; an indolicidin (anti-microbial peptide) suchas MX-594AN (Omniganin; CLS001); an indolicidin (anti-microbial peptide)such as Omnigard (MBI-226; CPI-226); an anti-microbial peptide such asan insect cecropin; an anti-microbial peptide such as a lactoferrin(talactoferrin); an LL-37/cathelicidin derivative (an anti-microbialpeptide) such as P60.4 (OP-145); a magainin (an anti-microbial peptide)such as Pexiganan (MSI-78; Suponex); a protegrin (an anti-microbialpeptide) such as IB-367 (Iseganan); an agan peptide; a beta-natriureticpeptide such as Natrecor, or Noratak (Nesiritide), or ularitide;bivalarudin (Angiomax), a thrombin inhibitor; a C peptide derivative; acalcitonin such as Miacalcin (Fortical); an enkephalin derivative; anerythropoiesis-stimulating peptide such as Hematide; a gap junctionmodulator such as Danegaptide (ZP1609); a gastrin-releasing peptide; aghrelin; a glucagon-like peptide; a glucagon-like peptide-2 analog suchas ZP1846 or ZP1848; a glucosaminyl muramyl dipeptide such as GMDP; aglycopeptide antibiotic such as Oritavancin; a teicoplanin derivativesuch as Dalbavancin; a gonadotropin releasing hormone (GnRH) such asZoladex (Lupon) or Triptorelin; a histone deacetylase (HDAC) inhibitordepsipeptide such as PM02734 (Irvalec); an integrin such aseptifibatide; an insulin analog such as Humulog; a kahalalidedepsipeptide such as PM02734; a kallikrein inhibitor such as Kalbitor(ecallantide); an antibiotic such as Telavancin; a lipopeptide such asCubicin or MX-2401; a lutenizing hormone releasing hormone (LHRH) suchas goserelin; an LHRH synthetic decapeptide agonist analog such asTreistar (triptorelin pamoate); an LHRH such as Eligard; an M2 proteinchannel peptide inhibitor; metreleptin; a melanocortin receptor agonistpeptide such as bremalanotide/PT-141; a melanocortin; a muramyltripeptide such as Mepact (mifamurtide); a myelin basic protein peptidesuch as MBP 8298 (dirucotide); an N-type voltage-gated calcium channelblocker such as Ziconotide (Prialt); a parathyroid hormone peptide; aparathyroid analog such as 768974; a peptide hormone analog such asUGP281; a prostaglandin F2-α receptor inhibitor such as PDC31; aprotease inhibitor such as PPL-100; surfaxin; a thromobspondin-1 (TSP-1)mimetic such as CVX-045 or ABT 510; a vasoactive intestinal peptide;vasopressin; a Y2R agonist peptide such as RG7089; obinepeptide; andTM30339.

Drugs for Conjugation to an Aldehyde-Tagged Immunoglobulin Polypeptide

Any of a number of drugs are suitable for use, or can be modified to berendered suitable for use, as a reactive partner to conjugate to anald-tagged-Ig polypeptide. Exemplary drugs include small molecule drugsand peptide drugs. Thus, the present disclosure provides drug-antibodyconjugates.

“Small molecule drug” as used herein refers to a compound, e.g., anorganic compound, which exhibits a pharmaceutical activity of interestand which is generally of a molecular weight of no greater than about800 Da, or no greater than 2000 Da, but can encompass molecules of up to5 kDa and can be as large as about 10 kDa. A small inorganic moleculerefers to a molecule containing no carbon atoms, while a small organicmolecule refers to a compound containing at least one carbon atom.

“Peptide drug” as used herein refers to amino-acid containing polymericcompounds, and is meant to encompass naturally-occurring andnon-naturally-occurring peptides, oligopeptides, cyclic peptides,polypeptides, and proteins, as well as peptide mimetics. The peptidedrugs may be obtained by chemical synthesis or be produced from agenetically encoded source (e.g., recombinant source). Peptide drugs canrange in molecular weight, and can be from 200 Da to 10 kDa or greaterin molecular weight.

In some cases, the drug is a cancer chemotherapeutic agent. For example,where an antibody has specificity for a tumor cell, the antibody can bemodified as described herein to include an aldehyde tag, can besubsequently converted to an FGly-modified antibody, and can then beconjugated to a cancer chemotherapeutic agent. Cancer chemotherapeuticagents include non-peptidic (i.e., non-proteinaceous) compounds thatreduce proliferation of cancer cells, and encompass cytotoxic agents andcytostatic agents. Non-limiting examples of chemotherapeutic agentsinclude alkylating agents, nitrosoureas, antimetabolites, antitumorantibiotics, plant (vinca) alkaloids, and steroid hormones. Peptidiccompounds can also be used.

Suitable cancer chemotherapeutic agents include dolastatin and activeanalogs and derivatives thereof; and auristatin and active analogs andderivatives thereof. See, e.g., WO 96/33212, WO 96/14856, and U.S. Pat.No. 6,323,315. For example, dolastatin 10 or auristatin PE can beincluded in an antibody-drug conjugate of the present disclosure.Suitable cancer chemotherapeutic agents also include maytansinoids andactive analogs and derivatives thereof (see, e.g., EP 1391213; and Liuet al (1996) Proc. Natl. Acad. Sci. USA 93:8618-8623); and duocarmycinsand active analogs and derivatives thereof (e.g., including thesynthetic analogues, KW-2189 and CB 1-TM1).

Agents that act to reduce cellular proliferation are known in the artand widely used. Such agents include alkylating agents, such as nitrogenmustards, nitrosoureas, ethylenimine derivatives, alkyl sulfonates, andtriazenes, including, but not limited to, mechlorethamine,cyclophosphamide (CYTOXAN™), melphalan (L-sarcolysin), carmustine(BCNU), lomustine (CCNU), semustine (methyl-CCNU), streptozocin,chlorozotocin, uracil mustard, chlormethine, ifosfamide, chlorambucil,pipobroman, triethylenemelamine, triethylenethiophosphoramine, busulfan,dacarbazine, and temozolomide.

Antimetabolite agents include folic acid analogs, pyrimidine analogs,purine analogs, and adenosine deaminase inhibitors, including, but notlimited to, cytarabine (CYTOSAR-U™), cytosine arabinoside, fluorouracil(5-FU), floxuridine (FudR), 6-thioguanine, 6-mercaptopurine (6-MP),pentostatin, 5-fluorouracil (5-FU), methotrexate,10-propargyl-5,8-dideazafolate (PDDF, CB3717),5,8-dideazatetrahydrofolic acid (DDATHF), leucovorin, fludarabinephosphate, pentostatine, and gemcitabine.

Suitable natural products and their derivatives, (e.g., vinca alkaloids,antitumor antibiotics, enzymes, lymphokines, and epipodophyllotoxins),include, but are not limited to, Ara-C, paclitaxel (TAXOL®), docetaxel(TAXOTERE®), deoxycoformycin, mitomycin-C, L-asparaginase, azathioprine;brequinar; alkaloids, e.g. vincristine, vinblastine, vinorelbine,vindesine, etc.; podophyllotoxins, e.g. etoposide, teniposide, etc.;antibiotics, e.g. anthracycline, daunorubicin hydrochloride (daunomycin,rubidomycin, cerubidine), idarubicin, doxorubicin, epirubicin andmorpholino derivatives, etc.; phenoxizone biscyclopeptides, e.g.dactinomycin; basic glycopeptides, e.g. bleomycin; anthraquinoneglycosides, e.g. plicamycin (mithramycin); anthracenediones, e.g.mitoxantrone; azirinopyrrolo indolediones, e.g. mitomycin; macrocyclicimmunosuppressants, e.g. cyclosporine, FK-506 (tacrolimus, PROGRAF™),rapamycin, etc.; and the like.

Other anti-proliferative cytotoxic agents are navelbene, CPT-11,anastrazole, letrazole, capecitabine, reloxafine, cyclophosphamide,ifosamide, and droloxafine.

Microtubule affecting agents that have antiproliferative activity arealso suitable for use and include, but are not limited to,allocolchicine (NSC 406042), Halichondrin B (NSC 609395), colchicine(NSC 757), colchicine derivatives (e.g., NSC 33410), dolstatin 10 (NSC376128), maytansine (NSC 153858), rhizoxin (NSC 332598), paclitaxel(TAXOL®), TAXOL® derivatives, docetaxel (TAXOTERE®), thiocolchicine (NSC361792), trityl cysterin, vinblastine sulfate, vincristine sulfate,natural and synthetic epothilones including but not limited to,eopthilone A, epothilone B, discodermolide; estramustine, nocodazole,and the like.

Hormone modulators and steroids (including synthetic analogs) that aresuitable for use include, but are not limited to, adrenocorticosteroids,e.g. prednisone, dexamethasone, etc.; estrogens and pregestins, e.g.hydroxyprogesterone caproate, medroxyprogesterone acetate, megestrolacetate, estradiol, clomiphene, tamoxifen; etc.; and adrenocorticalsuppressants, e.g. aminoglutethimide; 17α-ethinylestradiol;diethylstilbestrol, testosterone, fluoxymesterone, dromostanolonepropionate, testolactone, methylprednisolone, methyl-testosterone,prednisolone, triamcinolone, chlorotrianisene, hydroxyprogesterone,aminoglutethimide, estramustine, medroxyprogesterone acetate,leuprolide, Flutamide (DROGENIL®), Toremifene (FARESTON®), and(ZOLADEX®). Estrogens stimulate proliferation and differentiation;therefore compounds that bind to the estrogen receptor are used to blockthis activity. Corticosteroids may inhibit T cell proliferation.

Other suitable chemotherapeutic agents include metal complexes, e.g.cisplatin (cis-DDP), carboplatin, etc.; ureas, e.g. hydroxyurea; andhydrazines, e.g. N-methylhydrazine; epidophyllotoxin; a topoisomeraseinhibitor; procarbazine; mitoxantrone; leucovorin; tegafur; etc. Otheranti-proliferative agents of interest include immunosuppressants, e.g.mycophenolic acid, thalidomide, desoxyspergualin, azasporine,leflunomide, mizoribine, azaspirane (SKF 105685); IRESSA® (ZD 1839,4-(3-chloro-4-fluorophenylamino)-7-methoxy-6-(3-(4-morpholinyl)propoxy)quinazoline);etc.

Taxanes are suitable for use. “Taxanes” include paclitaxel, as well asany active taxane derivative or pro-drug. “Paclitaxel” (which should beunderstood herein to include analogues, formulations, and derivativessuch as, for example, docetaxel, TAXOL™, TAXOTERE™ (a formulation ofdocetaxel), 10-desacetyl analogs of paclitaxel and3′N-desbenzoyl-3′N-t-butoxycarbonyl analogs of paclitaxel) may bereadily prepared utilizing techniques known to those skilled in the art(see also WO 94/07882, WO 94/07881, WO 94/07880, WO 94/07876, WO93/23555, WO 93/10076; U.S. Pat. Nos. 5,294,637; 5,283,253; 5,279,949;5,274,137; 5,202,448; 5,200,534; 5,229,529; and EP 590,267), or obtainedfrom a variety of commercial sources, including for example, SigmaChemical Co., St. Louis, Mo. (T7402 from Taxus brevifolia; or T-1912from Taxus yannanensis).

Paclitaxel should be understood to refer to not only the commonchemically available form of paclitaxel, but analogs and derivatives(e.g., TAXOTERE docetaxel, as noted above) and paclitaxel conjugates(e.g., paclitaxel-PEG, paclitaxel-dextran, or paclitaxel-xylose).

Also included within the term “taxane” are a variety of knownderivatives, including both hydrophilic derivatives, and hydrophobicderivatives. Taxane derivatives include, but not limited to, galactoseand mannose derivatives described in International Patent ApplicationNo. WO 99/18113; piperazino and other derivatives described in WO99/14209; taxane derivatives described in WO 99/09021, WO 98/22451, andU.S. Pat. No. 5,869,680; 6-thio derivatives described in WO 98/28288;sulfenamide derivatives described in U.S. Pat. No. 5,821,263; and taxolderivative described in U.S. Pat. No. 5,415,869. It further includesprodrugs of paclitaxel including, but not limited to, those described inWO 98/58927; WO 98/13059; and U.S. Pat. No. 5,824,701.

Biological response modifiers suitable for use include, but are notlimited to, (1) inhibitors of tyrosine kinase (RTK) activity; (2)inhibitors of serine/threonine kinase activity; (3) tumor-associatedantigen antagonists, such as antibodies that bind specifically to atumor antigen; (4) apoptosis receptor agonists; (5) interleukin-2; (6)IFN-α; (7) IFN-γ; (8) colony-stimulating factors; and (9) inhibitors ofangiogenesis.

Methods for Modification of Drugs to Contain Reactive Partner forReaction with 2-Formylglycine

Peptide drugs to be conjugated to an ald-tagged Ig polypeptide aremodified to incorporate a reactive partner for reaction with an aldehydeof the FGly residue of the ald-tagged Ig polypeptide. Since the methodsof ald-tagged polypeptide modification are compatible with conventionalchemical processes, any of a wide variety of commercially availablereagents can be used to accomplish conjugation. For example, aminooxy,hydrazide, hydrazine, or thiosemicarbazide derivatives of a number ofmoieties of interest are suitable reactive partners, and are readilyavailable or can be generated using standard chemical methods.

Where the drug is a peptide drug, the reactive moiety (e.g., aminooxy orhydrazide can be positioned at an N-terminal region, the N-terminus, aC-terminal region, the C-terminus, or at a position internal to thepeptide. For example, an exemplary method involves synthesizing apeptide drug having an aminooxy group. In this example, the peptide issynthesized from a Boc-protected precursor. An amino group of a peptidecan react with a compound comprising a carboxylic acid group andoxy-N-Boc group. As an example, the amino group of the peptide reactswith 3-(2,5-dioxopyrrolidin-1-yloxy)propanoic acid. Other variations onthe compound comprising a carboxylic acid group and oxy-N-protectinggroup can include different number of carbons in the alkylene linker andsubstituents on the alkylene linker. The reaction between the aminogroup of the peptide and the compound comprising a carboxylic acid groupand oxy-N-protecting group occurs through standard peptide couplingchemistry. Examples of peptide coupling reagents that can be usedinclude, but not limited to, DCC (dicyclohexylcarbodiimide), DIC(diisopropylcarbodiimide), di-p-toluoylcarbodiimide, BDP(1-benzotriazolediethylphosphate-1-cyclohexyl-3-(2-morpholinylethyl)carbodiimide), EDC(1-(3-dimethylaminopropyl-3-ethyl-carbodiimide hydrochloride), cyanuricfluoride, cyanuric chloride, TFFH (tetramethyl fluoroformamidiniumhexafluorophosphosphate), DPPA (diphenylphosphorazidate), BOP(benzotriazol-1-yloxytris(dimethylamino)phosphoniumhexafluorophosphate), HBTU(O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate),TBTU (O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluroniumtetrafluoroborate), TSTU(O—(N-succinimidyl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate),HATU (N-[(dimethylamino)-1-H-1,2,3-triazolo[4,5,6]-pyridin-1-ylmethylene]- —N-methylmethanaminiumhexafluorophosphate N-oxide), BOP-C1(bis(2-oxo-3-oxazolidinyl)phosphinic chloride), PyBOP((1-H-1,2,3-benzotriazol-1-yloxy)-tris(pyrrolidino)phosphoniumtetrafluorophopsphate), BrOP (bromotris(dimethylamino)phosphoniumhexafluorophosphate), DEPBT(3-(diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one) PyBrOP(bromotris(pyrrolidino)phosphonium hexafluorophosphate). As anon-limiting example, HOBt and DIC can be used as peptide couplingreagents.

Deprotection to expose the amino-oxy functionality is performed on thepeptide comprising an N-protecting group. Deprotection of theN-oxysuccinimide group, for example, occurs according to standarddeprotection conditions for a cyclic amide group. Deprotectingconditions can be found in Greene and Wuts, Protective Groups in OrganicChemistry, 3rd Ed., 1999, John Wiley & Sons, NY and Harrison et al.Certain deprotection conditions include a hydrazine reagent, aminoreagent, or sodium borohydride. Deprotection of a Boc protecting groupcan occur with TFA. Other reagents for deprotection include, but are notlimited to, hydrazine, methylhydrazine, phenylhydrazine, sodiumborohydride, and methylamine. The product and intermediates can bepurified by conventional means, such as HPLC purification.

The ordinarily skilled artisan will appreciate that factors such as pHand steric hindrance (i.e., the accessibility of the aldehyde tag toreaction with a reactive partner of interest) are of importance,Modifying reaction conditions to provide for optimal conjugationconditions is well within the skill of the ordinary artisan, and isroutine in the art. In general, it is normally desirable to conductionconjugation reactions at a pH below 7, with a pH of about 5.5, about 6,about 6.5, usually about 5.5 being optimal. Where conjugation isconducted with an aldehyde tagged polypeptide present in or on a livingcell, the conditions are selected so as to be physiologicallycompatible. For example, the pH can be dropped temporarily for a timesufficient to allow for the reaction to occur but within a periodtolerated by the cell having an aldehyde tag (e.g., from about 30 min to1 hour). Physiological conditions for conducting modification ofaldehyde tagged polypeptides on a cell surface can be similar to thoseused in a ketone-azide reaction in modification of cells bearingcell-surface azides (see, e.g., U.S. Pat. No. 6,570,040).

Small molecule compounds containing, or modified to contain, anα-nucleophilic group that serves as a reactive partner with an aldehydeof an FGly of an ald tag are also contemplated for use as drugs in theIg-drug conjugates of the present disclosure. General methods are knownin the art for chemical synthetic schemes and conditions useful forsynthesizing a compound of interest (see, e.g., Smith and March, March'sAdvanced Organic Chemistry: Reactions, Mechanisms, and Structure, FifthEdition, Wiley-Interscience, 2001; or Vogel, A Textbook of PracticalOrganic Chemistry, Including Qualitative Organic Analysis, FourthEdition, New York: Longman, 1978).

Thus small molecules having an aminooxy or hydrazone group for reactionwith an aldehyde of an FGly of an ald-tagged Ig polypeptide areavailable or can be readily synthesized. An aminooxy or hydrazone groupcan be installed onto a small molecule using standard syntheticchemistry techniques.

Ig Conjugates

In some embodiments, a subject Ig-conjugate is an antibody conjugate.For example, the present disclosure provides an antibody conjugate thatcomprises a subject Ig conjugate, where the antibody conjugate binds anantigen. The antibody conjugate can include a J¹ moiety covalently boundto an Ig heavy chain constant region only, covalently bound to an Iglight chain constant region only, or a J¹ moiety covalently bound to anIg heavy chain constant region and a J¹ moiety covalently bound to an Iglight chain constant region.

An antibody conjugate can have any of a variety of antigen-bindingspecificities, as described above, including, e.g., an antigen presenton a cancer cell; an antigen present on an autoimmune cell; an antigenpresent on a pathogenic microorganism; an antigen present on avirus-infected cell (e.g., a human immunodeficiency virus-infectedcell), e.g., CD4 or gp120; an antigen present on a diseased cell; andthe like. For example, an antibody conjugate can bind an antigen, asnoted above, where the antigen is present on the surface of the cell.

An antibody conjugate of the present disclosure can include, as the J¹moiety, any of a variety of compounds, as described above, e.g., a drug(e.g., a peptide drug, a small molecule drug, and the like), awater-soluble polymer, a detectable label, a synthetic peptide, etc.

An antibody conjugate of the present disclosure can bind antigen with asuitable binding affinity, e.g., from about 5×10⁻⁶ M to about 10⁻⁷ M,from about 10⁻⁷ M to about 5×10⁻⁷ M, from about 5×10⁻⁷ M to about 10⁻⁸M, from about 10⁻⁸ M to about 5×10⁻⁸ M, from about 5×10⁻⁸ M to about10⁻⁹ M, or a binding affinity greater than 10⁻⁹ M.

As non-limiting examples, a subject antibody conjugate can bind anantigen present on a cancer cell (e.g., a tumor-specific antigen; anantigen that is over-expressed on a cancer cell; etc.), and the J¹moiety can be a cytotoxic compound (e.g., a cytotoxic small molecule, acytotoxic synthetic peptide, etc.). For example, a subject antibodyconjugate can be specific for CD19, where the J¹ moiety is a cytotoxiccompound (e.g., a cytotoxic small molecule, a cytotoxic syntheticpeptide, etc.). As another example, a subject antibody conjugate can bespecific for CD22, where the J¹ moiety can be a cytotoxic compound(e.g., a cytotoxic small molecule, a cytotoxic synthetic peptide, etc.).

As further non-limiting examples, a subject antibody conjugate can bindan antigen present on a cell infected with a virus (e.g., where theantigen is encoded by the virus; where the antigen is expressed on acell type that is infected by a virus; etc.), and the J¹ moiety can be aviral fusion inhibitor. For example, a subject antibody conjugate canbind CD4, and the J¹ moiety can be a viral fusion inhibitor. As anotherexample, a subject antibody conjugate can bind gp120, and the J¹ moietycan be a viral fusion inhibitor.

Formulations

The Ig conjugates (including antibody conjugates) of the presentdisclosure can be formulated in a variety of different ways. In general,where the Ig conjugate is an Ig-drug conjugate, the Ig conjugate isformulated in a manner compatible with the drug conjugated to the Ig,the condition to be treated, and the route of administration to be used.

The Ig conjugate (e.g., Ig-drug conjugate) can be provided in anysuitable form, e.g., in the form of a pharmaceutically acceptable salt,and can be formulated for any suitable route of administration, e.g.,oral, topical or parenteral administration. Where the Ig conjugate isprovided as a liquid injectable (such as in those embodiments where theyare administered intravenously or directly into a tissue), the Igconjugate can be provided as a ready-to-use dosage form, or as areconstitutable storage-stable powder or liquid composed ofpharmaceutically acceptable carriers and excipients.

Methods for formulating Ig conjugates can be adapted from thoseavailable in the art. For example, Ig conjugates can be provided in apharmaceutical composition comprising an effective amount of a Igconjugate and a pharmaceutically acceptable carrier (e.g., saline). Thepharmaceutical composition may optionally include other additives (e.g.,buffers, stabilizers, preservatives, and the like). Of particularinterest in some embodiments are formulations that are suitable foradministration to a mammal, particularly those that are suitable foradministration to a human.

Methods of Treatment

The Ig-drug conjugates of the present disclosure find use in treatmentof a condition or disease in a subject that is amenable to treatment byadministration of the parent drug (i.e., the drug prior to conjugationto the Ig). By “treatment” is meant that at least an amelioration of thesymptoms associated with the condition afflicting the host is achieved,where amelioration is used in a broad sense to refer to at least areduction in the magnitude of a parameter, e.g. symptom, associated withthe condition being treated. As such, treatment also includes situationswhere the pathological condition, or at least symptoms associatedtherewith, are completely inhibited, e.g., prevented from happening, orstopped, e.g. terminated, such that the host no longer suffers from thecondition, or at least the symptoms that characterize the condition.Thus treatment includes: (i) prevention, that is, reducing the risk ofdevelopment of clinical symptoms, including causing the clinicalsymptoms not to develop, e.g., preventing disease progression to aharmful state; (ii) inhibition, that is, arresting the development orfurther development of clinical symptoms, e.g., mitigating or completelyinhibiting an active disease; and/or (iii) relief, that is, causing theregression of clinical symptoms.

In the context of cancer, the term “treating” includes any or all of:reducing growth of a solid tumor, inhibiting replication of cancercells, reducing overall tumor burden, and ameliorating one or moresymptoms associated with a cancer.

The subject to be treated can be one that is in need of therapy, wherethe host to be treated is one amenable to treatment using the parentdrug. Accordingly, a variety of subjects may be amenable to treatmentusing an Ig-drug conjugates disclosed herein. Generally such subjectsare “mammals”, with humans being of particular interest. Other subjectscan include domestic pets (e.g., dogs and cats), livestock (e.g., cows,pigs, goats, horses, and the like), rodents (e.g., mice, guinea pigs,and rats, e.g., as in animal models of disease), as well as non-humanprimates (e.g., chimpanzees, and monkeys.

The amount of Ig-drug conjugate administered can be initially determinedbased on guidance of a dose and/or dosage regimen of the parent drug. Ingeneral, the Ig-drug conjugates can provide for targeted delivery and/orenhanced serum half-life of the bound drug, thus providing for at leastone of reduced dose or reduced administrations in a dosage regimen. Thusthe Ig-drug conjugates can provide for reduced dose and/or reducedadministration in a dosage regimen relative to the parent drug prior tobeing conjugated in an Ig-drug conjugate of the present disclosure.

Furthermore, as noted above, because the Ig-drug conjugates can providefor controlled stoichiometry of drug delivery, dosages of Ig-drugconjugates can be calculated based on the number of drug moleculesprovided on a per Ig-drug conjugate basis.

In some embodiments, multiple doses of an Ig-drug conjugate areadministered. The frequency of administration of an Ig-drug conjugatecan vary depending on any of a variety of factors, e.g., severity of thesymptoms, etc. For example, in some embodiments, an Ig-drug conjugate isadministered once per month, twice per month, three times per month,every other week (qow), once per week (qw), twice per week (biw), threetimes per week (tiw), four times per week, five times per week, sixtimes per week, every other day (qod), daily (qd), twice a day (qid), orthree times a day (tid).

Methods of Treating Cancer

The present disclosure provides methods for delivering a cancerchemotherapeutic agent to an individual having a cancer. The methods areuseful for treating a wide variety of cancers, including carcinomas,sarcomas, leukemias, and lymphomas.

Carcinomas that can be treated using a subject method include, but arenot limited to, esophageal carcinoma, hepatocellular carcinoma, basalcell carcinoma (a form of skin cancer), squamous cell carcinoma (varioustissues), bladder carcinoma, including transitional cell carcinoma (amalignant neoplasm of the bladder), bronchogenic carcinoma, coloncarcinoma, colorectal carcinoma, gastric carcinoma, lung carcinoma,including small cell carcinoma and non-small cell carcinoma of the lung,adrenocortical carcinoma, thyroid carcinoma, pancreatic carcinoma,breast carcinoma, ovarian carcinoma, prostate carcinoma, adenocarcinoma,sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma,papillary adenocarcinoma, cystadenocarcinoma, medullary carcinoma, renalcell carcinoma, ductal carcinoma in situ or bile duct carcinoma,choriocarcinoma, seminoma, embryonal carcinoma, Wilm's tumor, cervicalcarcinoma, uterine carcinoma, testicular carcinoma, osteogeniccarcinoma, epithelial carcinoma, and nasopharyngeal carcinoma, etc.

Sarcomas that can be treated using a subject method include, but are notlimited to, fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma,chordoma, osteogenic sarcoma, osteosarcoma, angiosarcoma,endotheliosarcoma, lymphangiosarcoma, lymphangioendotheliosarcoma,synovioma, mesothelioma, Ewing's sarcoma, leiomyosarcoma,rhabdomyosarcoma, and other soft tissue sarcomas.

Other solid tumors that can be treated using a subject method include,but are not limited to, glioma, astrocytoma, medulloblastoma,craniopharyngioma, ependymoma, pinealoma, hemangioblastoma, acousticneuroma, oligodendroglioma, menangioma, melanoma, neuroblastoma, andretinoblastoma.

Leukemias that can be treated using a subject method include, but arenot limited to, a) chronic myeloproliferative syndromes (neoplasticdisorders of multipotential hematopoietic stem cells); b) acutemyelogenous leukemias (neoplastic transformation of a multipotentialhematopoietic stem cell or a hematopoietic cell of restricted lineagepotential; c) chronic lymphocytic leukemias (CLL; clonal proliferationof immunologically immature and functionally incompetent smalllymphocytes), including B-cell CLL, T-cell CLL prolymphocytic leukemia,and hairy cell leukemia; and d) acute lymphoblastic leukemias(characterized by accumulation of lymphoblasts). Lymphomas that can betreated using a subject method include, but are not limited to, B-celllymphomas (e.g., Burkitt's lymphoma); Hodgkin's lymphoma; non-Hodgkin'sB cell lymphoma; and the like.

EXAMPLES

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the present invention, and are not intended to limit thescope of what the inventors regard as their invention nor are theyintended to represent that the experiments below are all or the onlyexperiments performed. Efforts have been made to ensure accuracy withrespect to numbers used (e.g. amounts, temperature, etc.) but someexperimental errors and deviations should be accounted for. Unlessindicated otherwise, parts are parts by weight, molecular weight isweight average molecular weight, temperature is in degrees Celsius, andpressure is at or near atmospheric. Standard abbreviations may be used,e.g., bp, base pair(s); kb, kilobase(s); pl, picoliter(s); s or sec,second(s); min, minute(s); h or hr, hour(s); aa, amino acid(s); kb,kilobase(s); bp, base pair(s); nt, nucleotide(s); i.m.,intramuscular(ly); i.p., intraperitoneal(ly); s.c., subcutaneous(ly);and the like.

Example 1: Cloning of CD19 and CD22 Specific Antibodies

Genes encoding the CD19 and CD22 specific variable light chain regionswere synthesized and cloned into a plasmid containing the human IgGkappa light chain constant region using NcoI and BsiWI restrictionsites. The light chain constant region plasmid was either wild-type orcontained LCTPSR (SEQ ID NO:17) or LATPSR (SEQ ID NO:24), which wereinserted into the plasmid using Quikchange mutagenesis.

Genes encoding the CD19 and CD22 specific variable heavy chain regionswere synthesized and cloned into a plasmid containing the human IgGheavy chain constant region using EcoRI and NheI restriction sites. Theheavy chain constant region plasmid was either wild-type or containedLCTPSR (SEQ ID NO:17) or LATPSR (SEQ ID NO:24), which were inserted intothe plasmid using Quikchange mutagenesis.

FIG. 3 shows amino acid sequences of anti-CD19 light chain (uppersequence) and heavy chain (lower sequence) constant regions, with anLCTPSR (SEQ ID NO:17) sulfatase motif in the heavy chain constantregion. The signal peptide is shown in lower-case letters; the variableregion is underlined; solvent-accessible loop regions in the constantregions are shown in bold and underlined. The LCTPSR (SEQ ID NO:17)sequence is shown in bold and double underlining. The initial methionine(M) present in the heavy and light chain amino acid sequences is forpurposes of facilitating expression and can be optionally present inthese and all heavy and light chains amino acid sequences describedherein.

Wild-Type Anti-CD19 and Anti-CD22 Sequences

Amino acid sequences of wild-type (not aldehyde-tagged) anti-CD22 heavyand light chains are shown in FIGS. 6B and 19B, respectively. Nucleotidesequences encoding wild-type (not aldehyde-tagged) anti-CD22 heavy andlight chains are shown in FIGS. 6A and 15A, respectively.

Amino acid sequences of wild-type (not aldehyde-tagged) anti-CD19 heavyand light chains are shown in FIGS. 19B and 31B, respectively.Nucleotide sequences encoding wild-type (not aldehyde-tagged) anti-CD19heavy and light chains are shown in FIGS. 19A and 31A, respectively.

Sequences of Anti-CD19 and Anti-CD22 Heavy Chains Modified to IncludeLCTPSR (SEQ ID NO:17)

Amino acid sequences of anti-CD22 heavy chain constant regions modifiedto include the aldehyde tag sequence LCTPSR (SEQ ID NO:17) (which isrecognized and converted by FGE) are shown in FIGS. 7B, 8B, and 9B,where the aldehyde tag is in the CH1 domain; FIGS. 11B, 12B and 13Bwhere the aldehyde tag is in the CH2 domain; FIG. 15B, where thealdehyde tag is in the CH2/CH3 region; and FIG. 17B, where the aldehydetag is near the C-terminus. FIGS. 7A, 8A, 9A, 11A, 12A, 13A, and 15Aprovide nucleotide sequences encoding the amino acid sequences shown inFIGS. 7A, 8B, 9B, 11B, 12B, 13B and 15B, respectively.

Amino acid sequences of anti-CD19 heavy chain constant regions modifiedto include the aldehyde tag sequence LCTPSR (SEQ ID NO:17) (which isrecognized and converted by FGE) are shown in FIG. 23B, where thealdehyde tag is in the CH1 domain; FIG. 25B, where the aldehyde tag isin the CH2 domain; FIG. 27B, where the aldehyde tag is in the CH2/CH3region; and FIG. 29B, where the aldehyde tag is near the C-terminus.FIGS. 19A, 21A, 23A, and 25A provide nucleotide sequences encoding theamino acid sequences shown in FIGS. 19B, 21B, 23B, and 25B,respectively.

Sequences of Anti-CD19 and Anti-CD22 Heavy Chains Modified to IncludeLATPSR (SEQ ID NO:24)

Amino acid sequences of anti-CD22 heavy chain constant regions modifiedto include the control sequence LATPSR (SEQ ID NO:24) (which is notrecognized by FGE) are shown in FIG. 10B, where the control sequence isin the CH1 domain; FIG. 14B, where the control sequence is in the CH2domain; FIG. 16B, where the control sequence is in the CH2/CH3 region;and FIG. 18B, where the control sequence is near the C-terminus. FIGS.10A, 14A, 16A, and 18A provide nucleotide sequences encoding the aminoacid sequences shown in FIGS. 10B, 14B, 16B, and 18B, respectively.

Amino acid sequences of anti-CD19 heavy chain constant regions modifiedto include the control sequence LATPSR (SEQ ID NO:24) (which is notrecognized by FGE) are shown in FIG. 24B, where the control sequence isin the CH1 domain; FIG. 26B, where the control sequence is in the CH2domain; FIG. 28B where the control sequence is in the CH2/CH3 region;and FIG. 30B, where the control sequence is near the C-terminus.

Sequences of Anti-CD19 and Anti-CD22 Light Chains Modified to IncludeLCTPSR (SEQ ID NO:17)

An amino acid sequence of an anti-CD22 light chain constant regionmodified to include the aldehyde tag sequence LCTPSR (SEQ ID NO:17) isshown in FIG. 20B. FIG. 20A provides a nucleotide sequence encoding theamino acid sequence shown in FIG. 20B. FIG. 21B provides an amino acidsequence of an anti-CD22 light chain constant region modified to includethe control sequence LATPSR (SEQ ID NO:24); FIG. 21A provides anucleotide sequence encoding the amino acid sequence shown in FIG. 21B.

An amino acid sequence of an anti-CD19 light chain constant regionmodified to include the aldehyde tag sequence LCTPSR (SEQ ID NO:17) isshown in FIG. 32B. FIG. 32A provides a nucleotide sequence encoding theamino acid sequence shown in FIG. 32B. FIG. 33B provides an amino acidsequence of an anti-CD22 light chain constant region modified to includethe control sequence LATPSR (SEQ ID NO:24); FIG. 33A provides anucleotide sequence encoding the amino acid sequence shown in FIG. 33B.

Example 2: Expressing and Purifying CD19 and CD22 Specific Antibodies

Plasmids containing genes encoding the CD19 or CD22 specific heavy andlight chains were transfected into CHO-K1 cells stably expressing humanFGE using Lipofectamine 2000 transfection reagent. 12 μg of the heavyand light chain plasmids were used for every 10 mL of Opti-MEMserum-free medium used. After 5h at 37° C., the Opti-MEM was removed andEx-Cell 325 protein-free medium was added. After 72 h at 37° C., themedia was collected and cleared of debris. Cleared medium was combinedwith Protein A binding buffer and Protein A resin and incubated withrotation for 1h at room temperature (RT). The mixture was added to acolumn to let the unbound material flow through. The resin was washedwith Protein A binding buffer and then eluted 5 with Protein A elutionbuffer.

Anti-CD19 and anti-CD22 heavy chain constant regions were modified toinclude an aldehyde tag in the CH1 domain, the CH2 domain, or the CH3domain. Anti-CD19 and anti-CD22 light chains were also modified toinclude an aldehyde tag. Aldehyde-tagged anti-CD19 and aldehyde-taggedanti-CD22 antibodies were subjected to protein blot analysis. Theresults are shown in FIG. 4.

As shown in FIG. 4, inclusion of an aldehyde tag did not disrupt proteinexpression, folding, or secretion. “Ald” refers to modification of theconstant region to include LCTPSR (SEQ ID NO:17), a sequence that isrecognized by FGE. “C2A” refers to modification of the constant regionto include “LATPSR (SEQ ID NO:24),” a sequence that is not recognized byFGE.

The aldehyde-tagged anti-CD19 and anti-CD22 antibodies include aldehydetags in both heavy and light chains.

Example 3: Conjugation of Aminooxy Flag® Peptide to PurifiedAldehyde-Tagged Antibody

Purified antibodies were combined with 1 mM aminooxy FLAG® peptide and100 mM MES buffer pH 5.5 for 16h at room temperature (RT). Samples wererun on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) gel and subjected to Western Blot analysis using ananti-FLAG® antibody to detect conjugation of the FLAG® peptide to theantibody.

The results are shown in FIG. 5. FIG. 5 depicts protein blot analysis ofaldehyde-tagged anti-CD19 and aldehyde-tagged anti-CD22 antibodies thatwere chemically conjugated with aminooxy-FLAG®.

FIG. 5A depicts a schematic of protein expression followed by aldehydespecific chemical conjugation. A western blot, probed with goatanti-human IgG or with anti anti-FLAG® antibody, illustrates an exampleof protein conjugation. No labeling was observed with the C2A(LATPSR)-tagged antibody (lower panel).

FIG. 5B depicts labeling with aminooxy FLAG® to the tagged anti-CD19 andAnti-CD22 IgGs. The protein loading and labeling was monitored byWestern blot. “CtoA” refers to antibodies modified to include the LATPSR(SEQ ID NO:24) sequence.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processstep or steps, to the objective, spirit and scope of the presentinvention. All such modifications are intended to be within the scope ofthe claims appended hereto.

What is claimed is:
 1. An immunoglobulin (Ig) polypeptide comprising anIgG1 heavy chain constant region comprising the amino acid sequenceNSGALCTPSRGVHTFPAVLQSSGL (SEQ ID NO:235).
 2. An antibody comprising theIg polypeptide of claim
 1. 3. An Ig polypeptide comprising a2-formylglycine (FGly) moiety, wherein the immunoglobulin (Ig)polypeptide comprises an IgG1 heavy chain constant region comprising theamino acid sequence NSGAL(FGly)TPSRGVHTFPAVLQSSGL (SEQ ID NO:239).
 4. Anantibody comprising the Ig polypeptide of claim
 3. 5. An antibodyconjugate comprising an Ig conjugate, wherein the immunoglobulin (Ig)conjugate comprises an IgG1 heavy chain polypeptide and a covalentlybound moiety, wherein the IgG1 heavy chain polypeptide comprises aconstant region comprising the amino acid sequenceNSGAL(FGly′)TPSRGVHTFPAVLQSSGL (SEQ ID NO:244), and wherein FGly′ is aformylglycine residue covalently bound to the moiety.
 6. The antibodyconjugate of claim 5, wherein FGly′ has the formula:

wherein J1 is the covalently bound moiety; each L1 is independentlyselected from alkylene, substituted alkylene, alkenylene, substitutedalkenylene, alkynylene, arylene, substituted arylene, cycloalkylene,substituted cycloalkylene, heteroarylene, substituted heteroarylene,heterocyclene, substituted heterocyclene, acyl, amido, acyloxy,urethanylene, thioester, sulfonyl, sulfonamide, sulfonyl ester, O, S,NH, and substituted amine; and n is a number selected from zero to 40.7. The antibody conjugate of claim 5, wherein the moiety is selectedfrom a drug, a detectable label, a water-soluble polymer, and asynthetic peptide.
 8. The antibody conjugate of claim 5, wherein themoiety is a small molecule drug.
 9. The antibody conjugate of claim 8,wherein the small molecule drug is a cancer chemotherapeutic agent. 10.The antibody conjugate of claim 5, wherein the moiety is a water-solublepolymer.
 11. The antibody conjugate of claim 10, wherein thewater-soluble polymer is poly(ethylene glycol).
 12. The antibodyconjugate of claim 5, wherein the moiety is a detectable label.
 13. Theantibody conjugate of claim 12, wherein the detectable label is animaging agent.
 14. The antibody conjugate of claim 5, wherein theantibody specifically binds a tumor antigen on a cancer cell.
 15. Theantibody conjugate of claim 14, wherein the moiety is a cytotoxic agent.16. The antibody conjugate of claim 5, wherein the antibody conjugatespecifically binds an antigen on a cell infected by a virus.
 17. Theantibody conjugate of claim 16, wherein the antigen is encoded by thevirus.
 18. The antibody conjugate of claim 5, wherein the moiety is aviral fusion inhibitor.
 19. A formulation comprising: a) the antibodyconjugate of claim 5; and b) a pharmaceutically acceptable excipient.20. The Ig polypeptide of claim 1, comprising an IgG1 heavy chainconstant region comprising the amino acid sequence set forth in SEQ IDNO: 259.